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PubMed2003

Anomalies of the auditory organ in trisomy 18 syndrome: human temporal bone histopathological study.

The purpose of this study was to define the histopathological changes in the temporal bone of a fetus with trisomy 18 syndrome, a stillborn due to perosplanchnia. Several anomalies were found including malformation of the auditory ossicles, residual mesenchyme in the middle ear, aberrant tensor tympani muscle, absence of stapedial tendon, aberrant lateral ampullary nerve and wide endolymphatic sinus. The incus body was deformed and separated from the long process by connective tissue and monocrural stapes was noted in the right ear. Three-dimensional reconstruction images provided a clear view of the auditory ossicle malformation. The abnormal findings in our case indicate that ear anomalies in this syndrome might be derived from the component around the first and second branchial arches.

Chromosomes, Human, Pair 18↗
PubMed2004

Variations in the tensor veli palatini muscle with special reference to its origin and insertion.

OBJECTIVE: Previous research on the tensor veli palatini muscle (TVP) has produced conflicting descriptions of its functions and topographical relationships with other orofacial structures. The goal of this study was to describe the morphology of the TVP in a systematic and comprehensive manner. METHODS: One hundred nineteen sides of 77 human heads from donated cadavers were partially dissected under a binocular microscope. Histological examination of the hard tissue-muscle interfaces was also undertaken. RESULTS: There were two adjacent origins of the TVP: the cranial base origin (CB origin) and the auditory tube cartilage origin (AT origin). The CB origin always lay anterior to the AT origin and there was no septum or loose tissue between the two muscular laminae leading from these origins. The muscle fibers converged on a central tendinous plate in the muscle belly, which gradually became a common tendon that rounded the pterygoid hamulus before inserting into the palatine aponeurosis. Notably, secondary insertions were found on the maxillary tuber (33.6%) and/or in the submucosal tissue near the palatoglossal arch (37.8%). Maxillary insertions were almost exclusively associated with an AT origin that was wide as or wider than the CB origin. Histological observations confirmed that the hamulus acted purely as a pulley and suggested that a connecting band to the tensor tympani had no or few functions of an intermediate tendon. CONCLUSIONS: The TVP appears to act as the dilator tubae and that this function can be maintained by preserving or reconstructing the maxillary insertion during push-back surgery, even if hamulotomy is necessary.

Adult↗
PubMed1987

Temporal bone histopathology in trisomy 18 syndrome: a report of two cases.

Temporal bone histopathological findings of two patients with trisomy 18 syndrome are described. Many of the abnormalities previously described were seen in the present cases; namely, atresia of the external auditory canal, aberrant course of the tensor tympani muscle, malformed stapes, aberrant course of the facial nerve with an obtuse angulation at the first genu and displacement of geniculate ganglion cells into the internal auditory canal, shortened cochlea with decreased spiral ganglion cell population, and vestibular anomalies, such as bony and membranous blockage of the superior semicircular canal. Moreover, an extremely underdeveloped malleus and incus continuous with a persistent Meckel's cartilage were observed.

Abnormalities, Multiple↗
PubMed1979

The noise protection effect of the stapedius reflex.

The purpose was to estimate the attenuation and protection effect of the acoustic stapedius reflex on the inner ear. The acoustic stapedius reflex was recorded by means of extratympanic manometry (ETM). This method was used, as it is able to differ between the stapedius and the tensor reflex. Patients with unilateral Bell's palsy were investigated during palsy time and after recovery. The amplitude of the contralateral acoustic stapedius reflex was used as a relative measure of the excitation of the cochlea on the affected side. The attenuation effect, 20 dB above the reflex threshold, was approximately 15 dB for all tested patients. After the ETM investigation a temporary threshold shift was shown on the affected side (average 34 dB). The hearing threshold on the healthy side was unchanged. Thus the attenuation effect of the acoustic stapedius reflex protects the inner ear from an acoustic damage. A protection effect of the tensor tympani was not demonstrated.

Audiometry↗
PubMed1979

Contraction properties and functional morphology of the avian stapedius muscle.

The influence of the stapedius muscle contraction on middle ear volume and acoustic impedance was investigated in the chicken, Gallus gallus. The time course of twitch responses to electrical stimulation (measured as volume and impedance changes) was found to be largely independent of the stimulus voltage, having a contraction time of 22 ms and a half-relaxation time of 22 ms. The stapedius muscle was therefore characterized as a fast twitch muscle. Slow contraction properties were also revealed: A summation of responses to repetitive stimulation beginning at 2.5 Hz and a slow decline to baseline were seen in volume and impedance change recordings. The morphological characteristics were consonant with that of a homogeneously fast muscle: Only fibres with high ATPase activity were identified and no fibres with "en grappe" or multiple innervation were observed. The slow characteristics were suggested to be due to visco-elastic elements in the middle ear. The chicken stapedius muscle is suggested to be analogous to both the stapedius and the tensor tympani of mammals.

Acoustic Impedance Tests↗
PubMedDate not supplied

Trauma of the ear from infrasound.

Twenty-eight chinchillas received continuous or intermittent infrasound (1, 10, 20 Hz) at 150, 160, or 170 dB SPL; there were 7 controls. Serial sections of the temporal bones were examined using light microscopy. Pathologies noted were tympanic membrane perforation, stapes subluxation, bleeding from the middle ear mucosa and tensor tympani, strial pathology, Reissner's membrane rupture, endolymphatic hydrops, saccular wall rupture, hair cell damage, and blood in the cochlear scalae. Continuous infrasound was more damaging than intermittent. Only continuous infrasound produced saccular pathology and perforations of the tympanic membrane. Of the other pathologies observed, continuous infrasound exposures produced 67% of the hair cell damage, 73% of the bleeding in the cochlear scalae, 83% of the strial pathology, and 78% of the cases of cochlear hydrops. 170-dB infrasound exposures produced the highest percentage of ears with pathologies of the three exposure intensities. As frequency increased the percentage of ears with pathologies decreased.

Animals↗
PubMedDate not supplied

The site of initial production and transport of effusion materials in otitis media serosa. A study on rat middle ear cavity.

The aim of this experimental study was to localize the site of the initial production of effusion in the middle ear cavity. Via the tympanic bulla the passage between the lateral attic compartment and the rest of the middle ear (isthmus tympanicus) was blocked with Gelfoam and/or the Eustachian tube likewise with a polyethylene tube in both normal and sympathectomized rats. Effusion was thus produced in the attic, while concomitantly dilated vessels were seen in the pars flaccida, which after a couple of days gradually withdrew in a medial direction to form a retraction pocket. Sympathectomy did not prevent the production of effusion. The stream of effusion was nasal to the promontorium and the tensor tympani muscle. Its transport seems to be influenced by the ventilation through the tympanic tube.

Animals↗
PubMedDate not supplied

Ultrastructure of middle ear mucosa in the Mongolian gerbil, Meriones unguiculatus.

The Mongolian gerbil is an easily maintained rodent which has been useful for investigations of the middle and inner ear. The gerbil may be used as an animal model for otitis media and cholesteatoma. The purpose of this study was to describe the ultrastructure of the epithelial and subepithelial lining of the gerbilline middle ear. The middle ear of the gerbil is lined by an epithelial membrane which is similar in cell type to human and guinea pig middle ear mucosa. The major part of the middle ear is lined with simple, non-keratinizing squamous cells with or without microvilli. Ciliated and secretory cells were concentrated around the Eustachian tube orifice; additionally, ciliated cells were seen in two distinct bands extending posteriorly below the cochlea in the hypotympanum and above the cochlea toward the tensor tympani muscle. The subepithelial region consists of fusiform cells (fibroblasts or 'surface osteocytes') and collagen adjacent to bone. These cell types and their distribution further supports the use of the gerbil as a model for human disease.

Animals↗
PubMedDate not supplied

Anatomical variations and relations of the bony portion of the eustachian tube.

The bony portion of the Eustachian tube was examined, using anatomical and histological methods, on 200 temporal bones of adults. This part of the tube averages 11.38 mm in length, its tympanic opening has an average diameter of 5.20 X 3.95 mm, and its lumen can be of an irregular (45%), rectangular (35%) or triangular (20%) shape. The dimensions of the bony portion of the tube diminish gradually toward the isthmus, so that in the middle the average diameter is 4.02 X 3 mm and at the level of the isthmus, 2.5 X 1.5 mm. The outer wall forms the tympanic plate of the tympanic bone, which in 65% of the cases is compact and in 35% finely pneumatized. On this wall bony trabeculae often appear, which more or less block the lumen of the tube. The medial part of the upper wall forms the bony septum toward the m. tensor tympani and the lateral represents the tegmen. The average distance from the lumen of the tube to the dura at the level of the tegmen is 3.62 mm. The tegmen above the tube may be pneumatized (45%) or compact (55%). The lower wall in 20% of the cases is represented by a shallow groove, and if formed is usually convex into the tube's lumen, but is less often concave. The jutting out of the lower wall is usually caused by its pneumatization.

Adult↗
PubMedDate not supplied

Pathology of the nervous arc of the acoustic reflexes.

A short comment is made on the pathological conditions of the input and efferent arc of the stapedius reflex. The modifications of this reflex during pathological and experimental inpairment of the intermediate portion of the arc, at the brain stem level, in human subjects are analyzed in more detail. The graphic and oscilloscopic records demonstrate a modification of the latency, amplitude and particularly of the speed of onset of the reflex. A concomitant modification of the electronystagmogram and tonal tests of lateralization is also demonstrated. Some abnormal responses observed in cases of facial palsy (efferent arc) as compared with electrogustometry and the problem of eliciting an isolated reflex contraction of the tensor tympani are briefly commented upon.

Acoustic Stimulation↗
PubMed1993

The use of the startle reflex measurement in patients with various types of fixation of the ossicular chain.

The results of startle and acoustic stapedius reflex measurements can be used to subclassify various types of fixation of the ossicular chain. Reflex measurements were performed on a group of subjects with normal hearing and on a group of patients with surgically verified ossicular chain fixation. In 97% of the subjects with normal hearing (n = 30), reproducible impedance changes were observed as part of a startle reaction and four different reaction patterns could be distinguished. In a subgroup of subjects with normal hearing who had a relatively, statistically significant, high acoustic reflex threshold, a characteristic response was found which was most probably caused by contraction of the tensor tympani muscle only. The same response was detected in 77% of the patients (n = 22) with otosclerosis. In the remaining 23%, no middle ear impedance changes occurred as part of a startle reaction. In five out of six patients with fixation of the malleus, no response was observed. Although the startle reflex measurement is a valuable tool for distinguishing between stapes fixation and multiple ossicular chain fixations, the results are not conclusive.

Acoustic Impedance Tests↗
PubMed1984

The isomyosins of rabbit middle ear muscles.

Isomyosins of the two middle ear muscles of rabbit have been separated by electrophoresis in non-dissociating conditions. Tensor tympani has four isomyosins called MM1 to MM4 by order of decreasing mobility. Stapedius has two isomyosins, similar to MM1 and MM4. MM1 and MM2 have the same mobility than FM2 and FM3, fast isomyosins observed in psoas. MM4 has the same mobility than IM, a slow isomyosin observed in extensor digitorum longus. MM3 is absent in soleus, psoas or extensor digitorum longus. Slow myosin (SM) of soleus and fast myosin (FM1) of psoas are not observed in middle ear muscles.

Animals↗
PubMed1977

Microsurgical exposure of the petrous portion of the carotid artery.

Occlusion of the cervical portion of the internal carotid artery (ICA) has been treated by vein graft bypass from the common carotid to the supraclinoid segment. However, this procedure has the disadvantages of requiring temporary occlusion of collateral flow, the short length of ICA available for anastomosis, and the retraction required for exposure of the supraclinoid area. In an attempt to find a more suitable bypass site for grafting, the petrous portion of 50 carotid arteries was studied in cadavers. It was found that there was a 1-cm length of the horizontal segment of the petrous carotid that could be exposed in the floor of the middle fossa lateral to the trigeminal nerve. This segment was covered by dura only or a thin layer of cartilage in approximately half of the specimens. In the remainder, there was often a thin shell of bone covering the artery, which could be drilled away. The petrous portion of the carotid artery had branches in only 38% of specimens, a Vidian branch in 30%, and a periosteal branch in 8%. The carotico-tympanic artery, previously reported to be the most common branch, was not found in a single case. These branches allow the retrograde flow needed to maintain the patency of this segment following proximal occlusions. The relationship of the carotid artery to structures include the cochlea, middle ear, Eustachian tube, tensor tympani muscle, geniculate ganglion, and facial, greater petrosal, and trigminal nerves.

Carotid Artery, Internal↗
PubMed2003

[Clinical evaluation of congenital cholesteatoma of the middle ear].

We conducted a retrospective study to identify the clinical features and surgical observations of congenital cholesteatoma. Sixty patients were diagnosed and underwent surgery for congenital cholesteatoma between April 1987 and May 2002. All diagnoses were made on the basis of two operative findings: 1. the tympanic membrane manifested neither retraction, perforation, nor granulation. 2. the tympanic membrane was not continuous with the cholesteatoma. In this series, congenital cholesteatoma accounted for 7% of all cholesteatomas (853 ears). The patient age ranged from 2 to 48 years. The male to female ratio was 4:1. Seventeen patients had multiple cholesteatoma. Fifty-three patients exhibited closed-type cholesteatomas, while the remaining 7 patients had open-type cholesteatomas that had formed as a flat surface of the epidermis. Patients with open-type cholesteatomas presented with a much more pronounced conductive hearing loss and ossicular erosion or malformation. Twenty-two patients with relatively small cholesteatomas were analyzed to estimate the origin of their cholesteatomas. Of the 22 patients, 13 had anterior superior quadrant (ASQ-type) and 9 had posterior superior quadrant (PSQ-type) cholesteatomas. The mean age at the time of detection was older in the PSQ-type group than in the ASQ-type group and the frequency of ossicular erosion or malformation was more prominent in the PSQ-type group than in the ASQ-type group. The primary site of origin was thought to be the portion between the tympanic ostium of the auditory canal and the semicanal for tensor tympani in the ASQ-type group and near the incudostapedial joint in the PSQ-type group. A planned staged procedure was performed in 29 patients, 15 patients (52%) had residual lesions situated mostly on the oval window, the round window, an exposed facial nerve or an exposed lateral semicircular canal. The frequency of residual lesions in patients who presented with extended, multiple cholesteatoma and those with ossicular malformation was comparable to the frequency of patients who did not present with these features.

Adolescent↗
PubMed1994

[Direct observation of the tympanic cavity by superfine fiberscopy through the eustachian tube].

It was impossible to observe directly the tympanic cavity with the ear drum intact. The superfine fiberscope, developed by the Department of Otolaryngology, Tokyo Medical College, makes it possible to observe the tympanic cavity through the eustachian tube without any surgical intervention such as myringotomy. This fiberscope is flexible and very fine, having an outer diameter of 0.6-0.8mm. Using this new fiberscope, the following structures can be observed: the handle of the malleus, the long process of the incus, the incudostapedial joint, the head of the stapes, the crus of the stapes, the tendon of the tensor tympani muscle and the promontory. Observation results are presented for 138 ears with various disorders: cholesteatoma, tympanosclerosis, congenital malformation, ossicular dislocation, otosclerosis, otitis media with effusion, chronic otitis media, etc. All patients could be tested with local anesthesia in the outpatient clinic except very young children. The findings were easily recorded on either photographs or video tapes. This superfine fiberscope was of great value in the diagnosis of pathologies affecting middle ear structures in outpatient clinics, since no surgical intervention was necessary in the procedure. In addition, it was very useful for making highly detailed studies and for discussion after the examination.

Adolescent↗
PubMed2002

[Measurement of facial nerve blood flow in rabbits using laser Doppler flowmetry].

OBJECTIVE: To study the microcirculation disorder of the facial nerve entrapment in rabbits. METHODS: Laser Doppler Flowmetry (LDF) was used in the blood flow measurement of the horizontal segment of the facial nerve and other adjacent structures in 32 New Zealand White rabbits. The repeated test was used to evaluate the stability of LDF. RESULTS: An animal model was established to study the microcirculation of the facial nerve in rabbits. The record of repeat test showed that LDF is a stable method. LDF of the horizontal segment of the facial nerve is higher in the proximal end but lower in distal. LDF in the distal part of the horizontal facial nerve (57.96 +/- 24.59) is higher than the semicircle canal(21.16 +/- 6.39), the medial wall of the attic(21.17 +/- 6.21), the tendon of the tensor tympani muscle(10.40 +/- 5.97) and other adjacent structures (P < 0.05). LDF probe may become a detector for surgeon to find the facial nerve in the complicated operation fields and prevent the iatrogenic facial paralysis. Because the press on the nerve can induce the decrease of the LDF, we estimate LDF may be very useful in the study of facial nerve entrapment. CONCLUSIONS: LDF is a new, stable, objective method for microcirculation study on facial nerve, and very useful in pathophysiological investigation of peripheral facial paralysis.

Animals↗
PubMed2003

[Myoclonus of the middle ear. A rare, differential diagnosis for objective tinnitus].

UNLABELLED: PRESENT STATE OF KNOWLEDGE: Myoclonus of the musculature of the soft palate, as well as middle ear myoclonus resulting from abnormal contraction of the stapedius and/or tensor tympani muscles, are two of the rarer causes in the differential diagnose of objective tinnitus. AIM: Here we describe a childhood case. To our knowledge, no case has previously been described in a child. METHODS AND RESULTS: Our patient isa six year old girl with a bilateral 40 dB sensorineural hearing loss and a high frequency objective tinnitus. The methods of clinical investigation, possible differential diagnoses and therapeutic options are discussed. CONCLUSION: Both intracerebral changes and systemic disorders have been described in some adult patients with palatal myoclonus. Whereas these cases are unlikely to respond to therapy, there is the chance that in some patients with objective tinnitus middle ear myoclonus may be the cause. This should be excluded by appropriate otoneurological investigations.

Acoustic Impedance Tests↗
PubMed1992

Autograft tragal and conchal palisade cartilage and perichondrium in tympanomastoid reconstruction.

Since Utech's introduction of cartilage as a columella in ear surgery in 1969, we have used tragal and conchal autografts for reconstruction of the tympanic membrane and the auditory canal wall in 13,000 cases. As large pieces of cartilage can twist in later years, we place palisaded cartilage fragments with perichondrium parallel to the manubrium of the malleus in type I tympanoplasties and in type II or III procedures parallel to the long process of the incus. The "annulus-stapes plate" in type III tympanoplasties replaces the function of the incus (and malleus), crossing the promontory and reducing adhesions. A "tunnelplasty" keeps the eustachian tube entrance open with the semiring of cartilage ("simmering") apposed to the inside of the annulus, reconstructing the tympanomeatal niche. The "architrave" created rests on the tensor tympani while the palisaded epitympanum and antrum plasty allows ventilation of the antrum. Mastoid obliteration is performed with an autogenous perichondrial transplant to which the palisaded incised cartilage portions adhere, adapting to the underlying structure.

Cholesteatoma↗