Several neuropeptides including substance P (SP) are regarded as central nervous system neurotransmitters or neuromodulators, and in this report their localization in the inner earhas been investigated immunohistochemically. The localization of4neuropeptides (substance P, calcitonin gene-related peptide, Enkephalin, Neuropeptide Y) in decalcified inner ear tissue was investigated by the avidin-biotin peroxidase complex (ABC) method. The results were compared with the results obtained by Ylikoski et al. using frozen sections to determine whether immunohistochemical studies of decalcified specimens are possible, and we concluded that even after decalcification of the tissue in EDTA, the structure of these neuropeptides does not alter and can be detected by ABC method.
Recent experimental studies by several in vestigators have shown that application of propylene glycol, a solvent commonly used in topical ear preparations, to the middle ear cavity of laboratory animals can produce severe inflammation and cholesteatoma in the middle ear. Our study was designed first to determine whether or not cholesteatoma formation following this experimental procedure in animals would be reproducible and, if reproducible, toelucidate the possible pathological mechanism to induce any lesion under experimental conditions. Our observation were based on histopathological study of the temporal bones of8chinchillas, which were obtained at 6months after instillation of propylene glycol into the middle ear. They were processed for celloidin embedding and serial sectioning, and examinedby light microscopy. The results of the present study showed that cholesteatoma could be produced consistently by the application of high concentration of propylene glycol to chinchilla middle ears and that the epithelium of cholesteatoma was surrounded by abundant granulation tissue, which infiltrated and eroded the bony walls of the middle ear. Further, in some animals a typical pathological appearance showing middle ear effusion and atelectasis without apparent perforation of the tympanic membrane was also observed.
Results of posterior canal wall reconstruction after canal down procedure were analized in50 ears of47cases. They included31ears with otitis media (OM group) and19ears with cholesteatoma (CH group). The results were classified as follows: Group A; no retraction, Group B; retracted but clean. Group C; retracted with otorrhea or debris, Group D; reoperated.Group A and B are classified as the success group and group C and D as the failure group. The results are as follows: 1. There were no difference in results between the materials used for reconstruction, such as autologous fascia or bone, and homologous cartilage in both groups. 2. The over all results were better in OM group (success rate77%) than in CH group (42%). 3. Otorrhea was recurred more frequently in OM group and retraction was more frequently in CH group. 4. By reconstruction combined with anterior tympanotomy, the success rate in OM group improved from78% to100%, and in CH group from14% to54%. 5. As the over all success rate (64%) was not sufficient, even though by combination withanterior tympanotomy (success rate71%), the posterior canal wall should be preserved at the primary operation.
An new office technique of conservative myringoplasty with lyophylized homograft dura and fibrin glue was carried out in 150 ears to close a central perforation of the typmpanic membrane. These patients who underwent this technique revealed a 58.7% success rate initially and 70.7% success rate totally. We apply Zentel's solution with a cotton tipped applicator for local anesthesia. Then the perforation edges are removed and the eardrum de-epithelized for 1mm around the perforation with a pick or hook. A lyophilized homograft dura is taken out of its sterile bag, fashioned according to the size and shape of the perforation, and lay under it with fibrin glue, just as the underlay technique of conventional myringoplasty. It is supported with small pieces of Gelfoam and adhered with fibrin glue. The external ear canal is not packed post-operatively. The procedure takes approximately 10 minutes, and the patient may return to regular work. The patients are asked to avoid water into theear and to take antibiotics for one week. The routine follow-up was done in every one month. When the dura is adhered two or four weeks later, the perforation is usually healed. Ifit is not, the operation should be repeated. Only two perforations expanded postoperatively but there were no serious complications among 150 cases. This conventional myringoplasty is recommended for patients whose middle ear has no or minimal pathology because it is simple, time-saving and money-saving.
Five patients with petrosal cholesteatomas are presented. Two of them were thought to be congenital cholesteatomas originated in the petrous apex, and two were congenital cholesteatomas originated in the attic which extended medially, and the other one was thought to beacquired. Two cases of relatively small cholesteatomas underwent exteriorization with partial labyrinthectomy, and their cavities have been kept dry and widely communicated to the external auditory canal during the three years of observation period. In the other three cholesteatomas we were obliged to abandon their complete removal because firm adhesion of the matrix to the widely exposed middle cranial fossa dura was observed. One of thesepatients underwent marsupialization of cholesteatoma, in which the matrix was also adherent to the carotid artery as well as the jugular bulb. Although the cavity has the dangling fallopian canal and the exposed carotid artery, this patient has been doing well during three and a half years postoperatively. In the other two cases the operated cavity was obliterated by a large piece of abdominal fat since very remarkable protrusion of the middle cranial fossa dura to the operated cavity was found after debulking of the cholesteatoma. Three years' follow-up by magnetic resonance imaging (MRI) showed no sign of re-growth of the disease. In cases of petrosal cholesteatoma in which total excision or marsupialization is not possible, obliteration of the operated cavity by a fat graft may be safer withthe advent ofMRI which enable us to detect signs of re-formation of the disease.
The width of the external aperture of the vestibular aqueduct was measured in vivo of various ages by the surf ace reconstruction of three-dimensional images. Seventy-two normal ears, 76chronic otitis media and 54 Meniere's disease were studied. The following results wereobtained. 1. In normal and chronic otitis media, there was no significant difference between children (<15 years, average age: 9.9) and adults (>15years). The vestibular aqueduct developed before birth and did not develop thereafter. 2. The external aperture of the vestibular aqueduct in Meniere's disease was significantly small and showed hypoplasia in comparison with those of normal and chronic otitis media ears. 3. It was thought thatthe aqueductal hypoplasia found in Meniere's disease might occur prior to birth, and that some kinds of congenital factors are involved in the pathology of Meniere's disease.
Computer-aided three-dimensional reconstruction of inner ear anomalies was performed in the temporal bone histologic sections from a case of CHARGE association. Reconstructions were performed on the bony labyrinth, membranous labyrinth and inner ear sensory organs of both ears. The cochlea was hypoplastic, with only two turns. The utricle and the semicircular canals were completely missing, while the saccule was present. The vestibular aqueduct and the endolymphatic sac were hypoplastic. The findings were similar in both ears. Three-dimensional reconstruction was quite useful for understanding stereoscopic configurations of these anomalies. The application of semitransparent display function made it possibleto view the internal structures, and thus facilitated the understanding of the spatial relationships of these structures. Cochlear length was measured by the computer from the reconstructed images of the organ of Corti. The length of the right organ of Corti was24.9mm, and that of the left was21.8mm. Three-dimensional reconstruction of the temporal bone from histologic sections is useful not only for the stereoscopic understanding of anatomy and pathology, but also for various measurements of temporal bone structures.
Cockayne has described a syndrome of dwarfism with retinal atrophy and deafness in 1936 and 1946. Since then, over 130 cases have been reported. We examined two patients with confirmed Cockayne's syndrome and assessed their hearing by means of auditory brainstem response (ABR) audiometry together with other objective audiometric measures, since conventional diagnostic audiometric procedures were not applicable to the patients because of the severity of their mental deficiency. In a male patient who had been followed up for approximately 7 years (from the ages of 1 to 8 years), his auditory function was found to deteriorate progressively as he grew older. At the age of 1year and 5 months, his ABR waveform on both earshad been well defined with nearly normal latencies to click signals at 80dB (nHL), but at the age of 7, the ABR revealed no recognizable waves except for a questionable V wave on either ear to maximum click signals. In another patient (9-year-old female), the ABR showed no response on both ears to click signals at the intensity limits of the equipment and she was judged as having nearly total deafness. It is probable that the hearing losses in Cockayne's syndrome are aggrevated rapidly along with mental and physical deteriorations and possibly caused by the lesions in the retrocochlear site, particularly in the brainstem and upper central auditory pathway as a result of diffuse degenerative process in the CNS during the course of the disease.
To detect the electromechanical phenomenon in the cochlea, we recorded acoustic emissions (sound pressure near the tympanic membrane) evoked by extracochlear electrical stimulation, and observed their changes after the administration of the following drugs. After injection of 400mg/kg of aspirin intravenously, the waves of electrically evoked acoustic emissions and their peaks in the frequency analysis disappeared either reversibly or irreversibly. After injection of kanamycin 400mg/kg intramuscularly and ethacrynic acid 40mg/kg intravenously, the waves of electrically evoked acoustic emissions and their peaks in the frequency analysis disappeared irreversibly. This physiologoical vulnerability suggests thatcochlear hair cells are the biophysical origin of the acoustic emissions evoked by electrical pulses. And the waves of electrically evoked acoustic emissions and their peaks in thefrequency analysis are supposed to be available to monitor the hair cell function.
A superior sagittal sinus thrombosis was found in a 35-year-old female presenting with acute sensorineural deafness at the onset of the disease. Examinations revealed intact eardrums and bilateral sensorineural deafness in thelow tones though she complained of hearing loss and tinnitus only in the left ear. Oxygen therapy in high barometric pressure and steroid therapy were started under the diagnosis of bilateral sudden deafness. However, thepatient felt numbness in the right forearm and found a limp in the leg on the 5 th day after admission, and the symptoms rapidly worsended. Severe headache, dysarthria and disturbance of consciousness appeared on the 6th day. Superior sagittal sinus thrombosis was diagnosed by CT scans which revealed an empty delta sign in the sagittal sinus and signs of intracranial hypertension such as elimination of gyrus shadows and small lateral ventricles. Abnormal neural findings including hearing loss were rapidly improved after treatment for high intracranial pressure. The possibility of a lesion in the central nervous system should be kept in mind in the case having variable bilateral low tones deafness of sudden onset.
The treatment of sudden deafness remains largely empiric. Various kinds of therapies have been applied though the cause of sudden deafness is uncertain. Some of them are seemed to be effective, but the evaluations of their efficacies need to be more discussed. In this paper, four protocols of different methods of the therapy were applied at random in 23 cases of sudden deafness, who had visited Kitasato University Hospital within a week from the onset of the disease. Examinations revealed sensorineural hearing deafness of more than 50dB and of less than 90 dB in all patients. The evaluations of the treatments were studied prospectively, and the results were as follows; In eleven of all, the hearing were completely recovered to the normal range. The hearing impairment was improved more than 30 dB in six cases and improved less than 30 dB in three cases but it did not change in three patients. The total effective rate by the treatments was 74%. The four protocols of the different therapies, such as stellate ganglion block (SGB), prostaglandin E1, low molecular dextran, and steroids were statistically compared. However, there was no significantdifference of therapeutic efficacy between the groups of SGB and non-SGB, between the groups of prostaglandin E1 and low molecular dextran and between the groups of betamethasone and prednisolone.
It is well known that multiple sclerosis is a demyelinating disease of multiple neurologicsigns and symptoms, but sudden sensorineural hearing loss is an uncommon manifestation. Wereport a rare case of multiple sclerosis in a 17- year-old female with sudden hearing loss. She showed obvious waves of delayed evoked otoacoustic emissions, despite a profound sensorineural hearing loss in pure tone audiograms and abnormal auditory brainstem responses in her left ear. These results indicate her normal cochlear function and retrocochlear dysfunction. Magnetic resonance imaging revealed several multiple sclerosis plaques. One month after the initial examination, her hearing recovered completely. This case report demonstrates the value of delayed evoked otoacoustic emissions in differential diagnosis.
Acute low-tone sensorineural hearing loss (ALHL) appears to be one of the relatively common otologic disorders that rather frequently encountered in clinical practice. It is characterized clinically by the features that: 1) the onset is acute or sudden, 2) the etiology remains obscure, 3) the hearing loss is strictly sensorineural in nature, restricted to the low frequency range (125, 250 and 500 Hz), and usually unilateral. We retrospectivelystudied 127 patients with this disorder over a period of 6 years and 8 months and comparedwith 105 patients with sudden deafness (SD) who were treated at our clinic during a similar time span. It was found that there was a marked sex predominance for females (male-female ratio=37: 90) and that it occurred in rather younger population as compared with sudden deafness. As for the prognosis, most patients of ALHL showed a hearing recovery more rapidly than sudden deafness. Younger individuals with this disorder frequently showed hypotension and positive Schellong's test results. Interestingly, in two cases of SD their audiometric configuration coincided well with ALHL diagnostic criteria during their clinical course. Thus, it may be speculated that there are some common pathognomonic conditions or factors in the auditory system to provoke both ALHL and sudden deafness, although the clinicalfeatures quite differ from each other.
Six male patients complained of vertigo or disequilibrium accompanied with occupational hearing loss. Two of them worked in very noisy places for three years in the past and theothers have been working for 15 years or more. Their audiogram showed bilateral C5dip or high tone hearing loss. All of them were suffering from unilateral or bilateral tinnitus. Three of them (group A) have often felt static and gait imbalances while the others (group B) have experienced repeated rotatory vertiginous attacks. All cases of group Bshowed positional or positioning vertigo, rotatory nystagmus and decreases of caloric response. Onthe contrary, all cases of group A did not show any nystagmus or abnormal caloricresponse. The authors speculated that the patients of group A have received excessive stress by noisy circumstance in long terms, and this stress could cause insufficiency of cardiovascular system, vertebrobasilar arteries and autonomic nerve system. In the patients of group B, their inner ears were damaged not only in the cochlear but also in the vestibularsystems because of exposure to high intensity noise for a long period of time.
Test batteries of electrocochleography (EcochG) and evoked otoacoustic emission (e-OAE) were performed in a 57-year-old woman with sensorineural deafness and bilateral facial and vocal cord paralyses. Recordings of AP, SP and CM were made with the use of the transtympanic needle electrode technique. The e-OAE were recorded with an acoustic probe N-1 inserted into the external ear canal. Click acoustic stimulation was used for the measurement ofAP and SP. Short tone bursts were employed to evoke both e-OAE and CM. The broad AP waveforms with the monophasic shape in response to click stimulus were observed in both ears.Input-output curves of AP amplitude in both ears showed only H-part, in which the amplitude of N1increased minimally with increasing intensity (L-response). The EcochG data showed enhancement of the negative SP (dominant-SP). The broadening of the AP, SP waveforms in this case might be due to the superimposition upon the monophasic AP waveform of the dominant-SP. Delayed CM which followed CM were not recorded in both ears. Detection thresholds of the CM in right ear were almost the same as those of normal subjects andwere about 20 dB higher in the left ear. Fast and slow components of acoustic oscillation appearing within 20 ms were definitely obtained in this case. The detection thresholds ofboth components, however were raised slightly above those of normal ears. The conventional psychoacoustic examination and the findings of ABR and SR suggested that the retrocochlear deafness might result mainly from brain stem lesions. The EcochG and e-OAE findingswere also suggestive of the pathphysiology of the cochlea with the impaiment at AP (N1) level and the damaged outer hair cells.
The facial nerve was stimulated via the parotid duct to record the antidromically evoked facial nerve response in13normal subjects. A patient with chronic otitis media operated on with the open method and another patient whose intratemporal facial canal was exposed intraoperatively were also studied as control subjects. A thin stimulating catheter electrode was inserted into the parotid duct. The nerve potential was recorded in the external auditory canal near the eardrum. The response recorded in the external auditory canal consisted of a small potential complex with short latency and a large potential complex with long latency. The potential with long latency had similar latency of compound muscle action potentials recorded simultaneously from the orbicularis oris muscle. Changes of latency, with moving the stimulating site or the recording site, showed that a small potential was elicited from more central portion of the facial nerve than a stimulating site. The potential with long latency disappeared under a muscle relaxant intraoperatively. The facts showedthat the potential with short latency was the antidromically evoked facial nerve response and another was compound muscle action potentials of the facial mimic muscles. Identification of the nerve potential was easy, because stimulation via the parotid duct diminished the initial stimulating artifacts.