[Observation of human stapes and simulated stapedial lesion based on Micro-CT scanning].

Objective:The aim of this study is to understand the imaging morphology of the humerus morphology and its associated simulated lesions, and to provide information for related research. Method:Six adult cadaveric heads fixed by formaldehyde solution (12 sides of the tibia) were used. One of the cadaveric heads (two sides of the tibia) was perforated and fractured under the microscope.The remaining 5 (10 sides) were used. The humerus was used for morphological measurements of the tibia.The tibia (12 sides) was taken out, Micro-CT scan was performed, and two-dimensional and three-dimensional reconstruction were performed using software such as Mimics 17.0 software. Result:①Stapedial morphologic observation:the head,curs and footplate of the stapes and the adjacent structures can be well displayed on two dimensional structures.②Quantitative measurements and statistics: There were no significant statistic differences about the data that had been measured between the right ears and the left ears.③Micro-CT was more clearly in displaying the precise structure of human stapes and the stapedial minute lesion comparing with that of HRCT. Conclusion:Micro-CT can accurately and clearly display the structure, morphology and simulated lesions (model) of the tibia, which provides important reference materials and methods for related research.

Endolymphatic sac surgery versus tenotomy of the stapedius and tensor tympani muscles in the management of patients with unilateral definite Meniere's disease.

This study aims to compare the outcomes of patients with Meniere's disease submitted to either endolymphatic mastoid shunt (ES) or tenotomy of the stapedius and tensor tympani muscles (TSTM). This is a retrospective chart review of patients treated with ES or TSTM between 2000 and 2010 and followed up for at least 12 months. The main outcomes were represented by: (1) vertigo class, hearing stage and functional level according to the American Academy of Otolaryngology-Head and Neck Surgery criteria; (2) adjustment of dizziness handicap inventory (DHI) and (3) complete and substantial vertigo control using the Kaplan-Meier survival method. Sixty-three patients met the inclusion criteria: 34 underwent ES and 29 TSTM. The baseline demographic characteristics, the hearing stage, the functional level, the DHI and hearing levels were not different between the two groups. No significant difference in vertigo class was demonstrated: 66 % of TSTM patients attained class A compared to 44 % in the ES group (p = 0.14). Kaplan-Meier survival curves specific to class A showed significant differences, favoring TSTM (log-rank test, p = 0.022). TSTM patients demonstrated significantly improved functional level (p = 0.0004) and improved DHI scores (p = 0.001). Eight ES patients (25 %) demanded a second surgical attempt compared to none in the TSTM. Aural fullness was significantly improved in TSTM group (p = 0.01), while the difference in tinnitus improvement was non-significant. Hearing preservation was significantly better in TSTM group (p = 0.001). TSTM is a safe surgical procedure, with significant vertigo control rates, and important hearing preservation rates. More patients and longer follow-up are needed to support our preliminary findings.

Division of the stapedial tendon results in noise-induced damage to the inner ear.

BACKGROUND: The effect of division of the stapedial tendon on susceptibility to noise-induced inner ear damage has not been previously studied. This study aimed to evaluate the effects of noise exposure following division of the stapedial tendon in guinea pigs. MATERIAL AND METHODS: Ten adult albino guinea pigs were used. The stapedial tendon of each right ear was cut. The stapedial tendon in each left ear was left intact and these ears served as a control group. DPOAEs and ABR tests were performed before and 10 days after noise exposure. The animals were exposed to a 110-dB noise stimulus for 6 h in a silent room a week after surgery. Cochleas of the animals were removed, and inner and outer hair cells were examined under a light microscope. RESULTS: We found that noise exposure adversely affected DPOAE measurements at all frequencies except 2 KHz in experimental ears. Noise exposure also produced significantly elevated ABR thresholds in experimental ears at 2, 4, 8, and 16 KHz. On histopathological examination, we found a significantly greater prevalence of apoptotic cells in the experimental ears. CONCLUSIONS: Based on these findings, we can conclude that after division of the stapedial tendon, noise exposure may cause damage to the inner ear. This is the first study in the English literature that demonstrates the potential protective effect of the stapedial tendon against acoustic damage.

Prevalence of hearing loss in patients with late-onset Pompe disease: Audiological and otological consequences.

OBJECTIVE: The metabolic disorder Pompe disease mainly affects the skeletal muscle in adults. The hearing impairment due to stapedius muscle involvement in adult patients is not known. DESIGN: The frequency, severity, and type of hearing impairment was characterized prospectively using pure-tone audiometry, tympanometry, stapedial reflexes, otoacoustic emissions, and brainstem-evoked response audiometry in adult patients on enzyme replacement therapy for genetically confirmed Pompe disease. STUDY SAMPLE: 11 adult patients (median age: 47 years, range: 22-71). RESULTS: Four patients complained about subjective hearing disturbances. Using World Health Organization definition of hearing impairment, abnormal hearing thresholds resulting in mild hearing loss were found in 36% of patients. Compared to normative data (ISO 7029), the hearing threshold was below the median in all but three ears. Stapedial reflexes could not be elicited ipsilateral in 18% and contralateral in 36%. Auditory brainstem responses showed no retrocochlear pathology. CONCLUSIONS: The prevalence of hearing loss slightly exceeded the normative data of the general population. Consistent with previous studies the hearing impairment was usually mild. The percentage of pathological stapedial reflexes exceeded that of matched control subjects and suggests a selective involvement of the stapedius muscle, potentially as a sequela of Pompe disease.

Scleraxis is required for differentiation of the stapedius and tensor tympani tendons of the middle ear.

Scleraxis (Scx) is a basic helix-loop-helix transcription factor expressed in tendon and ligament progenitor cells and the differentiated cells within these connective tissues in the axial and appendicular skeleton. Unexpectedly, we found expression of the Scx transgenic reporter mouse, Scx-GFP, in interdental cells, sensory hair cells, and cochlear supporting cells at embryonic day 18.5 (E18.5). We evaluated Scx-null mice to gain insight into the function of Scx in the inner ear. Paradoxical hearing loss was detected in Scx-nulls, with ~50% of the mutants presenting elevated auditory thresholds. However, Scx-null mice have no obvious, gross alterations in cochlear morphology or cellular patterning. Moreover, we show that the elevated auditory thresholds correlate with middle ear infection. Laser interferometric measurement of sound-induced malleal movements in the infected Scx-nulls demonstrates increased impedance of the middle ear that accounts for the hearing loss observed. The vertebrate middle ear transmits vibrations of the tympanic membrane to the cochlea. The tensor tympani and stapedius muscles insert into the malleus and stapes via distinct tendons and mediate the middle ear muscle reflex that in part protects the inner ear from noise-induced damage. Nothing, however, is known about the development and function of these tendons. Scx is expressed in tendon progenitors at E14.5 and differentiated tenocytes of the stapedius and tensor tympani tendons at E16.5-18.5. Scx-nulls have dramatically shorter stapedius and tensor tympani tendons with altered extracellular matrix consistent with abnormal differentiation in which condensed tendon progenitors are inefficiently incorporated into the elongating tendons. Scx-GFP is the first transgenic reporter that identifies middle ear tendon lineages from the time of their formation through complete tendon maturation. Scx-null is the first genetically defined mouse model for abnormal middle ear tendon differentiation. Scx mouse models will facilitate studies of tendon and muscle formation and function in the middle ear.

Activation of middle-ear muscles by transcranial magnetic stimulation.

OBJECTIVES: To evaluate the reliability of transcranial magnetic stimulation in eliciting admittance changes due to activation of middle-ear muscles. METHODS: Admittance changes induced by transcranial magnetic stimulation at the inion were evaluated in eight normal subjects, two subjects with prelingual deafness and 22 patients suffering from other otological disorders characterised by absence of acoustic reflex. RESULTS: Responses showed a predominant negative peak in normal ears. Two small positive components, one preceding and the other following the negative deflection, were less consistently elicited. Only a positive wave was detected in otosclerotic subjects. Patients with tympanic membrane perforation or previous tympanoplasty with ossicular discontinuity did not show any response. CONCLUSIONS: Transcranial magnetic stimulation is able to activate both stapedius and tensor tympani muscles. In conjunction with admittance audiometry, it may represent a method of exploring the mechanics of the middle ear when acoustic reflex testing is not reliable. It can be helpful in the confirmation of stapes fixation when a severe to profound hearing loss is present.

[Degenerative changes in stapedius muscle morphology caused by aging].

Degenerative changes in the morphology of the stapedius muscle caused by aging using a collection of human temporal bones obtained by our department. The diameter of the muscle fibers, the variance in muscle fiber diameter, the ratios of intermuscular connective tissue and muscle to the area of the bone niche for the stapedius muscle, the number of muscle fibers around the tendon, and the adipose cell count were measured for each temporal bone. In total, 80 temporal bones were examined, excluding specimens with facial nerve degeneration, degenerative diseases, middle ear disease and leukemia. Between the ages of 38 fetal weeks and 9 years, the muscle fibers and thin and the variance in fiber diameter is small. The areas of intermuscular connective tissue, muscle and the number of muscle fibers around the tendon do not change between 38 fetal weeks and 60 years. All of the parameters measured showed no significant changes between the ages of 10 and 60 years. The variance in muscle fiber diameter began to increase in specimens aged 70 years or older because some of the muscle fibers had begun to atrophy. Adipose cells were sometimes observed in very old specimens. In contrast to the tensor tympani muscle, in which degenerative changes begin during childhood, atrophic degeneration of the stapedius muscle as a result of aging begins at a very late age. The difference in aging between the stapedius muscle and the tensor tympani muscle is probably related to evidence suggesting that the stapedius muscle contracts in response to acoustic stimulation.

[Tympanomastoid glomus tumor and persistent stapedial artery]. / Tumor glómico timpanomastoideo y persistencia de la arteria estapedial.

A case of tympanic glomic tumor associated with vascular malformation of the perifacial plexus is reported. The case and its possible relation with persistent stapedial artery are discussed. The embryological development of the middle-ear vessels and blood supply to glomic tumors were reviewed.

Middle ear and inner ear effects on clinical bone-conduction threshold.

The measurement of bone-conduction thresholds is an integral part of audiologic evaluation. The relationship between bone-conduction and air-conduction thresholds is the differentiating diagnostic indicator between conductive and sensorineural hearing loss. At the same time, the influence of middle ear and inner ear structures upon the bone-conduction response has been well documented. We present two cases illustrating this influence and attempt to explain the clinical bone-conduction thresholds with operative findings.

Prevalence of facial canal dehiscence and of persistent stapedial artery in the human middle ear: a report of 1000 temporal bones.

A total of 1000 temporal bones were used to study the prevalence of facial canal dehiscence and of persistent stapedial artery in detail. Of the temporal bones studied, 560 (56%) contained at least one facial canal dehiscence. There was a 76.3% prevalence of bilaterality of this canal wall gap. The most common site of dehiscence was the oval window area. The concept of microdehiscence of the facial canal is introduced. One third of the temporal bones observed had a microdehiscence of the facial canal, usually located at the oval window area (74.9%) and found bilaterally 40% of the time. The authors found a 0.48% prevalence (5 out of 1045) of persistent stapedial artery. This is the first histological study of temporal bones to report a prevalence of this vascular anomaly.

[Conductive deafness without perforation of tympanic membrane with reference to cases of undetermined incudostapedial joint disorder].

In order to elucidate the pathophysiology of an undetermined conductive deafness without perforation of the tympanic membrane, comparative study was made in several factor with conductive deafness which has normal tympanic membrane and may be due to inflammation. Differences and similarities in the manner of ossicular damage were discussed in these conductive deafness. The morbidity rate of conductive deafness without perforation of the tympanic membrane which was undetermined cause, was found in wide age group 7 to 56 years of age. The site of damage was found at portion of the incudostapedial joint. The origin of etiology was estimated may take part in inflammatory process. We emphasized that such as undetermined conductive deafness may increase according to increase of otitis media with effusion.

Surgically confirmed clinical otosclerosis among the Chinese.

We report herein on 163 cases of surgically confirmed otosclerosis among Chinese. Our results suggest significant racial differences between Chinese and whites in respect to the incidence of this disease, and the likelihood of a family history. Surgical and histopathological findings, while confirming otosclerosis identical to that experienced in whites, suggest that generally the disease is milder among Chinese. The sex ratio, age range, and bilateral involvement, on the other hand, were discovered to be basically similar between the two races. A detailed description is given of the postauricular surgical technique used, and it is argued that it may be more suitable in cases where there is a small ear canal, since the results achieved (80% success rate) are comparable with other reports.

Infiltration of the tensor tympani and stapedius muscles in otitis media. An experimental study in the cat.

A longitudinal sequential study of otitis media was done in an experimental animal (cat) using eustachian tube obstruction. Fifty animals were used. Cellular infiltration of the tensor tympani and stapedius muscles was studied in a continuum from day 1 to 6 months after inducing otitis media. We observed that there is infiltration of the connective tissue of both muscles in otitis media, and that the cellular changes follow the same pattern as that seen in the mucoperiostium and the round window of the middle ear, although to a lesser degree. In this first report of sequential changes in middle ear muscles in otitis media, clinical implications of these findings are discussed.