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Recent and future trends in the management of otosclerotic conductive hearing loss.

The protection of cochlear function following stapedectomy has emerged as the major problem in the surgical treatment of otosclerosis. Both immediate and delayed sensorineural losses continue to occur in spite of refinements of technique. The frequency and extent of these complications has been investigated by prospective and retrospective studies of the author's patients. It has been concluded that the size of the footplate fenestration plays a major role in the outcome, both immediately, and in the long term. Revision operations are necessary when initially good results rapidly deteriorate, both to resolve complications such as perilymphatic fistulae and also to restore function. Although second ear operations are usually worthwhile, they should be performed only when certain specific criteria have been met. The expected duration of unaided hearing gain, although often adequate when a standard large fenestra operation is performed, is considerably prolonged by restricting the size of the footplate to less than half its total area. For reasons unknown, bone conduction thresholds appear to be better, eventually, in operated as compared to unoperated ears.

Bone Conduction↗

Acoustic radiation from bone vibrators.

Our purpose was to investigate the influence of acoustic radiation produced by bone vibrators at 4000 Hz on bone conduction (BC) testing. In one study, BC thresholds were obtained with a Radioear B-70A, B-71, and B-72 vibrator when the subject's ear canal was unoccluded and occluded. In another study, probe-tube microphone measurements were made just inside the entrance to the ear canal for each vibrator and for an air conduction source at comparable sensation levels. Results of both studies were interpreted to indicate that the B-70A and B-71 produced minimal acoustic radiation. However, the B-72 was found to have excessive acoustic radiation which would be sufficient to influence BC thresholds and produce an invalid high-frequency air-bone gap.

Acoustics↗

Long-term observation on hearing change in patients with chronic otitis media.

OBJECTIVE: Very few reports are available in the literature to clarify the natural long course of hearing change in an individual patient with chronic otitis media (COM). We reviewed hearing change in patients suffering from perforated COM without an operation. METHODS: Eighty-seven ears of 70 patients had COM with tympanic perforation and were observed without an operation. The mean follow-up period was 10.7 years (5-22 years) and the mean age at the first examination was 51.3 years. To minimize the effect of aging, 23 patients with normal ear drums on the other side were further analyzed. RESULTS: All 87 ears tended to show deterioration of hearing gradually under long observation. In 23 patients, hearing deterioration was 0.13 dB/year in the control side and 0.61 dB/year in the COM side (P < 0.02). Although elevation of bone conduction hearing level tended to be larger at high frequencies than at low and middle frequencies, there was no significant difference between COM and normal ears. CONCLUSIONS: Air conduction hearing levels deteriorated with the passage of time and surgery is recommended at the early stage of COM to prevent progress of hearing loss.

Adult↗

Reassessment of high-frequency air-bone gaps in older adults.

In order to assess whether a high-frequency air-bone gap characteristically exists in older adults, air- and bone-conduction thresholds were measured for 147 ears from subjects ranging in age from 19 to 87 years. Results indicated that there were no apparent age-related effects, as evidenced by the mean data, the SDs, and scatterplots showing individual data points. However, a small number of older adults did have high-frequency air-bone gaps. In order to gain a better understanding of underlying causes, additional subjects over 50 years of age with high-frequency air-bone gaps were recruited. Ear-canal collapse did not appear to be a predominant underlying factor. Cerumen obstruction, healed tympanic membrane perforations, and an apparent loosening in the middle-ear system all were observed in ears with high-frequency air-bone gaps.

Adult↗

In vivo evaluation of plasma-sprayed wollastonite coating.

Wollastonite coatings were prepared by plasma spraying. The bioactivity of wollastonite coatings was investigated in vivo by implanting in dog's muscle, cortical bone and marrow, respectively. The behaviour of bone tissue around wollastonite coatings were examined by histological and SEM observation. After 1 month in the muscle, a bone-like apatite layer was found to form on the surface of the wollastonite coating. When implanted in cortical bone, histological observation demonstrated that bone tissue could extend and grow along the surface of the wollastonite coating. The coating bonded directly to the bone without any fibrous tissue, indicating good biocompatibility and bone conductivity. SEM and EDS analysis revealed that bone did not bond to wollastonite coating directly, but through a Ca/P layer. This suggested that the formation of bone-like apatite layer was very important for bonding to the bone tissue. The amount of bone-implant contact was also measured. Wollastonite coating was shown to stimulate more bone formation on its surface than titanium coating after implantation for 1 month, enhancing the short-term osseointegration properties of implant. The test in marrow indicated that wollastonite coatings could induce new bone formation on their surface showing good bone inductivity property.

Animals↗

Prefabricated ossicular homografts in middle ear reconstructions.

This paper is a review of 132 cases of ossicular reconstruction utilizing prefabricated homografts by clinical staff members of the UCLA Division of Head and Neck Surgery (specializing in ear surgery) in their private practice over the past decade. Another 20 cases completed over the past 2 1/2 years in the UCLA teaching programme are also reviewed. Although ossicular homografts have been used for some time in middle ear reconstruction, this report presents the innovation of prefabricating homografts into specific shapes that lend themselves appropriately to reconstruction problems. In such an ossicular bank, a variety of different shapes, in a number of sizes, is maintained for quick selection. This greatly decreases operating room time and, in addition, provides an effective method for ossicular reconstruction that has already been applied to a resident training programme. The cases in this review can be divided into 3 basic categories: (1) mastoidectomy ossicular reconstruction; (2) exploratory tympanotomy with reconstruction; (3) stapedectomy. This study indicates that ossicular homografts are very well tolerated in their new transplanted positions. Our very low extrusion rate, extremely rare evidence of absorption, and lack of foreign body reaction to these ossicles coincides with the experience of others. This is an advantage over plastic prostheses. In addition to pre- and postoperative air conduction level data, analysis of changes in bone conduction and speech discrimination scores are also presented to evaluate possible neurosensory damage related to manipulation in placing these ossicles.

Adult↗

Otosclerotic involvement of the cochlea: a histologic and audiologic study.

This study sought correlations between sensorineural hearing loss and otosclerotic endosteal involvement in 29 temporal bones examined histologically. The sensorineural hearing loss of the affected parts of the cochlea was determined by the last antemortum bone conduction audiogram available. There were eight temporal bones with only stapes footplate involvement, six with one discrete focus of otosclerotic endosteal involvement, and 15 with two or more foci of endosteal involvement. Analysis of audiometric data showed that the group of bones with two or more foci of endosteal involvement had a similar incidence of 45 dB sensorineural loss (9 of 15 or 60%) as did the group with no endosteal involvement (5 of 8 or 62%). The group with two or more foci had a greater incidence of 60 dB or greater sensorineural loss (46%) compared with the groups with none (12%) or one focus (16%) involved. Correlation between hearing loss and involvement of cochlear endosteum was poor. Correlation existed in only 2 of 15 ears with two or more foci involving the cochlear endosteum. There was no correlation in the other groups. It appears that cochlear endosteal involvement alone may not be sufficient explanation for the sensorineural hearing loss found with otosclerosis, except in the most severely involved ears.

Adult↗

High-resolution CT scanning and auditory brain stem response in congenital aural atresia: patient selection and surgical correlation.

Thirty patients with congenital aural atresia underwent CT scanning and/or auditory brain stem response (ABR) testing in a 20-month period. Eighteen patients had unilateral atresia and 12 had bilateral atresia. Twelve patients subsequently had surgery for repair of their atresia. CT scanning was not electively done until the patient was at least 2 years of age, while ABR testing was often performed in the first few months of life. Nineteen patients had CT scanning and 27 had ABR testing. The CT technique was found to offer specific advantages not previously observed in other methods of radiographic evaluation: (1) the course of the facial nerve was more easily traced and (2) the presence (or absence) of a stapes was more easily noted. The ABR was measured for monaural air-conduction as well as mastoid-placement bone conduction click stimuli; simultaneous multielectrode two- or four-channel recordings were employed. With this measuring technique it was not only possible to enhance wave I detection but, more important, the laterality of ABR wave I could be noted.

Acoustic Stimulation↗

Sound localization in subjects with impaired hearing. Spatial-discrimination and interaural-discrimination tests.

In order to get a systematic picture of how various hearing impairments and neurologic disorders may affect sound localization, psychophysical spatial- and lateralization-discrimination measurements were performed on 140 subjects, including 69 with different types of hearing impairments, 32 with neurological diseases, and 39 with normal hearing. The quantities measured were: in the freefield, the horizontal minimum audible angle (MAA) at eight reference azimuths around the head and the vertical MAA straight ahead; with headphones, the just-noticeable difference (JND) in interaural time delay and the JND in interaural intensity difference. The standard stimulus was broadband (0.25-10 kHz), pulsed (1-sec), noise presented at a suprathreshold level for both ears (65-100 dB SPL). The results show that there exist characteristic impairments of sound localization in the different types of hearing impairments tested. On a general level, the results are consistent with the concept that the localization of sound relies on a decision made by the central auditory system based on a number of cues present in the acoustic signal at the two ears. The cues tested in our study are: 1) the interaural time difference, 2) the interaural intensity difference, and 3) the spectrum of the received signal at each ear. At a more specific level, the sound localization impairments found in conductive hearing losses are interpreted as bone-conduction effects, the results found in sensorineural hearing losses are interpreted as consequences of impaired or preserved spectral processing, the results in neurinomas are interpreted as impaired signal transmission in the auditory nerves, and the results of subjects with central involvements suggest that separate processors exist at some level in the central auditory system for the different localization cues. Finally, comments are made about the practical clinical significance of sound localization tests in the audiological and neurological evaluation of patients.

Adolescent↗

[Preliminary result of allogenic bone and autogeneic-iliac bone in comminuted fracture reparation in rabbits].

OBJECTIVE: To observe the difference of the fracture reparation using autogeneic-iliac bone and allogenic bone. METHODS: Comminuted fracture of humerus in two sides were made in rabbits. Autogeneic-iliac bone was implanted in one side, while allogenic bone of equal capacity was implanted in the other side. General observation, X-ray, and HE histologic section were done when the rabbits were put to death in different stages. RESULTS: One week after implantation, the graft had been enclosed by connective tissue without infiltration of the inflammatory cells. At the 2nd week, the graft had been enclosed in osteoplastic granulation tissue, and the cartilage callus had formed. At the 3rd week, there had been broken sequestrum among the callus; the cartilage had actively formed the bone; and the medulla had been making. At the 4th week, the sequestrum had disappeared, and the mature callus had appeared; the osteoblasts had arranged in a line around the edge of the mature callus. At the 5th week, the callus was strong, compact and approached mature bones. At the 6th week, there had been the compact lamellar structures and the complete haversian's systems. There was no significant difference between callus of two sides by using image quantitative analysis in the 3rd, 4th week (P > 0.05). CONCLUSION: The allogenic bone has good histocompatibility and bone conduction effect, and can be used for bone transplantation substitute with autogenous-iliac bone.

Animals↗

[Long-term results of stapes surgery with the Schuknecht wire-teflon prosthesis].

Early and late postoperative findings in 78 cases of stapedial surgery with 0.6 mm Schuknecht Teflon Wire Pistons only, performed from 1983 to 1987, were analysed to evaluate the supposition of an inverse relationship of the size of the footplate fenestration and functional long-term results. In respect of the size of fenestration our surgical strategy resulted in 3 different situations: stapedotomy (26)--partial platinectomy (34)--stapedectomy (19). Mean air conduction thresholds for frequencies 0.5-4 kHz were evaluated preoperatively, one month and > 5 years postoperatively. The results were postoperatively significantly better in all 3 groups without significant intergroup differences. > 5 years postoperatively the best results were seen in the partial platinectomy group better than after stapedotomy and significantly better than in the stapedectomy group. With regard to overclosure, closure of the air bone gap and deterioration of bone conduction thresholds at 4 kHz for the same groups, no significant differences were noticed. In conclusion, the best long-term results were obtained after partial platinectomy, i.e. there was no inverse relation of the size of the footplate perforation and the best results. The perforation should be large enough to prevent tilting of the piston at the edge. Removal of larger parts should be omitted. In case of early mobilisation and stapedectomy good long-term results can still be expected.

Auditory Threshold↗

[Analysis of the results of hearing improvement after bilateral stapedectomy].

The authors present the results of hearing improvement in a group of 50 patients who underwent bilateral stapedotomy. For the estimation of hearing improvement after the surgery the following criteria were used: 1. a comparison of air and bone conduction thresholds before and after the surgery, 2. an airbone gap before and after the surgery according to Toss, 3. hearing improvement index and 4. bilateral hearing loss index.

Adolescent↗

[Suppression of evoked otoacoustic emissions by contralateral noise exposure in humans].

The effects of contralateral noise exposure on evoked otoacoustic emission (e-OAE) were investigated in 10 normal hearing subjects and 3 cases with unilateral deafness. The e-OAE was recorded by ILO88 and weighting noise was given to the contralateral ear (impaired side in unilateral deafness cases). The air conducted noise exposure showed suppressive effect on e-OAE along with the increase of noise stimulus intensity in normal hearing subjects, but did not in unilateral deafness cases. The degree of suppression in e-OAE was most remarkable in highest peak power between 1 kHz and 2 kHz in FFT picture and the mean value of maximal suppression in 10 normal hearing subjects was 2.2 dB. The bone conducted noise exposure showed no effects on e-OAE in either normal hearing subjects or unilateral deafness cases. It was suggested that the contralateral noise exposure could suppress the function of cochlear micromechanics probably via crossed olivocochlear bundle.

Acoustic Impedance Tests↗

Efficacy of evaluation of audiometric results after stapes surgery in otosclerosis. I. The effects of using different audiologic parameters and criteria on success rates.

The Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery proposed guidelines to provide more uniformity in reporting hearing results after middle ear surgery. One of the proposals was to include the hearing thresholds at 0.5, 1, 2, and 3 kHz in a 4-frequency pure-tone average (PTA) and to use post-operative bone-conduction (BC) levels rather than preoperative BC levels in describing postoperative air-bone gaps (ABGs). The hearing results of 451 stapes operations were evaluated to analyze to what extent the choice of different audiologic criteria affects success rates. It appeared that choice of PTA significantly affects postoperative gain in air-conduction thresholds and ABG levels. If one takes the improvements in speech-reception thresholds as the gold standard, the gain in air-conduction correlates best with a gain in speech-reception threshold if a higher frequency, such as 3 or 4 kHz, is included in a 4-frequency PTA. Also, choice of preoperative or postoperative BC in computing postoperative ABGs had a significant effect on the mean postoperative ABG levels, showing more favorable results with the use of preoperative BC thresholds.

Adolescent↗

[Recovery of hearing: results of delayed medical treatment in patients with idiopathic sudden hearing loss].

For the treatment of idiopathic sudden sensorineural hearing loss (ISSNHL), a variety of studies about intravenous drug administration with the beginning of treatment in the early period of less then one week after the onset of hearing loss have been performed. In contrast, very little information is available about the efficacy of intravenous drug therapy for ISSNHL with the beginning of treatment later than four weeks after the onset of hearing loss. In a retrospective chart review we studied the treatment results of 57 patients with ISSNHL with beginning of treatment later than four weeks after the onset of hearing loss with no spontaneous recovery of hearing. Patients received a treatment with intravenous administration of Dextran (concentration 40 g/l with NaCl 0.9%) and Procain-HCl (a derivative of the local anaesthetic lidocaine,400-800 mg in a 500 ml rheologic infusion of Dextran 40). 25% of the patients showed a significant improvement of 10 dB or more in hearing threshold at 1000 Hz measured in bone-conducted pure tone audiometry. In a subjective evaluation 53% of the patients noticed a subjective improvement of their individual hearing thresholds.

Adolescent↗

[Experimental stapesplasty with the CO2 laser].

Perforation of the footplate in otosclerosis can be performed accurately, when the large and high energetic CO2 laser focus is reduced to 0.5 mm in diameter by an aluminium diaphragm. The operation was performed on three dogs. BAEPs were evoked by bone-conducted acoustic stimuli. Hearing threshold was unchanged immediately after operation as well as after 2 and 6 weeks postoperatively. The new method has still to be performed in man.

Animals↗

Persistent inner ear injury after diving.

OBJECTIVE: The purpose of this multiple case report was to discuss the occurrence and cause of sudden sensorineural hearing loss after diving. STUDY DESIGN: The study design was a retrospective case review. SETTING: The study was conducted at an academic tertiary referral center. PATIENTS: In this multiple case report, two teenagers with unilateral sudden sensorineural hearing loss after diving, one from a starting block and one from a 1-m board, while performing school swimsports were included. INTERVENTION: The patients underwent diagnostic tympanotomy with sealing of the round and oval window membranes and a vasoactive rheologic therapy combined with corticosteroid treatment. MAIN OUTCOME MEASURES: The average pure-tone bone-conduction thresholds were calculated. The appearance of nystagmus, vertigo, and tinnitus was analyzed. RESULTS: Both patients experienced unilateral sudden deafness after performing a headfirst pike-type dive into a swimming pool. None of the patients contacted with the bottom of the pool. In one patient, a rupture of the round window was found intraoperatively. In the other patient, no rupture of the round or oval window was seen intraoperatively. In spite of sealing of the round window and application of vasoactive rheologic therapy, hearing did not improve significantly in either of the patients. CONCLUSION: Rupture of the round window may occur after diving even if the dive is performed from a low height into the water and the bottom of the pool is not contacted. Besides direct contusion to the external ear and barotrauma, other causes such as whiplash mechanism have to be considered.

Adolescent↗

[A practical method to differentiate the sensations of hearing and feeling (auditory and vibration threshold) in the low-frequency range (author's transl)].

An uncomplicated method to differentiate between an auditory and a vibration threshold. It is a well-known problem that it is very difficult or almost impossible to distinguish in a deaf person between the genuine auditory threshold, especially the bone conduction threshold, and a vibration threshold in the range of low frequencies up to 1000 cps. The studies conducted by the authors show that a frequency-modulated tone is extremely suitable for this purpose, because it is very easy to recognize a 5-6% frequency modulated tone of 5 dB (SL) by hearing, whereas it is almost impossible to detect it by feeling. The observations by Fastl (1978) regarding the large inter-individual variation of the frequency modulation threshold does not limit the study conducted by the authors, because the degree of modulation used is far above the threshold. It is not possible to use an amplitude-modulated tone for differentiation between the auditory and the vibration thresholds.

Audiometry↗