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The facial nerve in congenital middle ear malformations.

The two most common anomalies of the facial nerve encountered in patients with a congenital malformation of the middle ear are displacement of the nerve and lack of a bony cover, two conditions that place the nerve at risk of being injured by the unwary surgeon. Malformations of the stapes are often found in association with facial nerve anomalies and may range from underdevelopment to complete absence. A congenital absence of the oval window is not uncommon. The position of the facial nerve in relation to the location and maturation of the ossicles will determine the method of ossicular chain repair. Creation of a new oval window by drilling may require the surgeon to purposely displace the facial nerve to ensure a more direct alignment of the prosthesis with the vestibule. Any part of the incus or malleus may be contoured by drilling to accommodate the loop end of the wire-piston prosthesis. An aberrant course of the facial nerve was found in 13/54 (24%) ears having a congenital malformation of the middle ear. All 54 ears had a patent external ear canal and an identifiable tympanic membrane. Patients with atresia or stenosis of the external ear canal were specifically excluded from this study.

Chorda Tympani Nerve↗

Management of labyrinthine fistulae secondary to cholesteatoma.

Improvements in diagnosis and management of chronic ear disease in general and cholesteatoma in particular have led to a decreased incidence of serious labyrinthine complications. Unfortunately, significant disease still does occur and, if unrecognized, may result in significant morbidity. Labyrinthine fistulae secondary to cholesteatoma cause potentially irreversible symptoms such as hearing loss and vertigo. This study reviews 17 patients who developed labyrinthine fistula secondary to cholesteatoma. Sixteen involved the horizontal semicircular canal and one involved the oval window. The cholesteatoma matrix was removed in all cases and the underlying fistula repaired primarily. Cochlear function was preserved in all patients. Sixteen of 17 patients have had no further difficulty with vertigo beyond the immediate postoperative period. The evaluation and contemporary management of this difficult problem are discussed.

Adolescent↗

Immunolocalization of aquaporin CHIP in the guinea pig inner ear.

Aquaporin CHIP (AQP-CHIP) is a water channel protein previously identified in red blood cells and water transporting epithelia. The inner ear is an organ of hearing and balance whose normal function depends critically on maintenance of fluid homeostasis. In this study, AQP-CHIP, or a close homologue, was found in specific cells of the inner ear, as assessed by immunocytochemistry with the use of affinity-purified polyclonal antibodies against AQP-CHIP.AQP-CHIP was predominantly found in fibrocytes in close association with bone, including most of the cells lining the bony labyrinth and in fibrocytes lining the endolymphatic duct and sac. AQP-CHIP-positive cells not directly apposing bone include cells under the basilar membrane, some type III fibrocytes of the spiral ligament, fibrocytes of the spiral limbus, and the trabecular perilymphatic tissue extending from the membranous to the bony labyrinth. AQP-CHIP was also found in the periosteum of the middle ear and cranial bones, as well as in chondrocytes of the oval window and stapes. The distribution of AQP-CHIP in the inner ear suggests that AQP-CHIP may have special significance for maintenance of bone and the basilar membrane, and for function of the spiral ligament.

Animals↗

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↗

[Temporal bone histopathology in a case of trisomy 22-syndrome (author's transl)].

This premature female infant died soon after birth. She had numerous gross anomalies and was found on cytogenic studies to have Trisomy 22. Polytomographic and histologic studies of the left ear revealed multiple anomalies including complete aural atresia, non-pneumatization of the middle ear with a vertical shelf of bone in the mid portion of the middle ear, absence of the stapes and oval window and bony closure of the round window niche. The cochlea is flat in shape and shows one and a half turns with incomplete formation of the modiolus. The intersaccular septum is rudimentary but the spiral ganglion is clearly seen in Rosenthal's canal through the one and a half turns. The organ of Corti is well developed and contains hair cells. The stria vascularis is present. The utricular and saccular maculae as well as all cristae are well developed and contain hair cells. The saccular wall is collapsed onto an atrophic appearing otolithic membrane. The utricle is dilated, the lateral semicircular canal appears short and the bony canal is wide. The flattened and shortened cochlea with deformities of the cochlear duct, and the large vestibule resembles Mondinis dysplasia.

Abnormalities, Multiple↗

[Functional long-term results after open cholesteatoma surgery and ossiculoplasty with allogenic ossicles in adulthood].

BACKGROUND: Characteristic features of cholesteatoma of the middle ear are destruction of the bone and a high tendency for recurrent disease. The choice of surgical procedure is determined by audiological results and the rate of recurrent cholesteatoma. PATIENTS: One hundred fifty patients who underwent primary cholesteatoma surgery were investigated 3-5 years postoperatively. Preoperative and postoperative audiological results and rate of revision surgery were compared for the respective surgical procedures. All cholesteatomas were treated with an open surgical technique. The lateral attic walls and cholesteatomas were removed. RESULTS: Cholesteotoma recurred in 15 patients (10%). Primary reconstruction of the ossicular chain with a tympanoplasty (type III) was performed in 98 patients in the first operation. Approximately 80% of patients treated with a type III tympanoplasty had a maximum postoperative air-bone gap of 20 dB in the main speech range, depending on the frequency. In about 50% of patients, this value was 10 dB or less. Comparison of preoperative and postoperative conductive hearing loss between 250 Hz and 8000 Hz revealed an improvement (p < 0.05) of 10 dB (500 Hz, 3000 Hz, 4000 Hz) and 15 dB (250 Hz, 1500 Hz, 2000 Hz, 8000 Hz). CONCLUSIONS: In our opinion, a second look operation should be performed in cases where a large cholesteatoma cannot be removed with sufficient reliability. This applies especially to a cholesteatoma in the oval window. Here, we suggest second-look surgery after one year.

Adolescent↗

The round window in acute hearing loss.

Sensorineural hearing loss has various etiologies. One of them is perilymphatic fistula, which is observed in (1) congenital malformation of the internal ear in children: (2) after operations on the oval window (stapedectomy, interposition); (3) in cases of head trauma, and (4) in acute hearing loss of unknown origin. The authors report 5 of 19 cases of acute hearing loss observed at the ORL Clinic in Kraków and operated on by exploratory tympanotomy. In 4 of them, rupture of the round window membrane (secondary tympanic membrane) was found. A hypothesis for the rupture mechanism is presented.

Adolescent↗

Reconstructive techniques for tympanosclerosis.

Tympanosclerosis is found in more than 30% of patients with chronic ear disease. Clinically significant tympanosclerosis is defined as that affecting the surgical procedure by requiring removal to effect a hearing improvement. This type is seen in less than half of all patients with tympanosclerosis. The incidence and patterns of involvement are documented for 352 of the author's surgical patients subdivided into two groups: one operated on in the early 1960s and another observed more than 15 years later. The surgical techniques employed for hearing restoration are described, as are the hearing results obtained. The findings would indicate that tympanosclerosis is amenable to surgical correction, with a success rate approximately that of nontympanosclerotic ears. The special techniques needed to avoid complications when the disease invades the oval window are emphasized.

Chronic Disease↗

[Otorhinolaryngologic aspects of diving sports].

ENT disorders are the most common of all medical problems of diving. This review summarizes the specific conditions and ENT diseases in Scuba diving. During compression failure to equalize the pressure of air-filled cavities surrounded by bone deprives the middle ear or sinuses of aeration. Middle ear barotrauma is the most common barotrauma encountered in divers while sinus barotrauma and especially inner ear barotrauma (with rupture of the round or oval window) are less common. Decompression sickness in primarily the result of inert gas bubbles; deafness and vertigo may result if the inner ear is involved. The ENT examination necessary for assessment of diving fitness focuses on the middle and inner ear as well as the nose, sinuses and larynx. A list of ENT contra-indications is presented that mandate temporary or permanent disqualification from diving.

Barotrauma↗

Middle and inner ear: improved depiction with multiplanar reconstruction of volumetric CT data.

Many anatomic structures of the middle and inner ear are not optimally depicted at computed tomography (CT) with image reconstruction in the standard axial and coronal planes. Recent advances in multidetector CT, including the development of scanners with 32 detector rows, allow the acquisition of isotropic voxels that can be reconstructed in any plane of section. This technique gives radiologists the opportunity to visualize the anatomic structures of the middle and inner ear (the ossicular chain, stapedial footplate-oval window complex, round window, cochlea, vestibular aqueduct, and bones of the superior semicircular canal and facial nerve canal) in greater detail and may help increase the accuracy of CT for the diagnosis of diseases of the middle and inner ear.

Ear Diseases↗

Transient evoked otoacoustic emissions in nonsurgical ear.

Several studies have reported contralateral hearing deficits following ear surgery. This study aimed to evaluate changes in micromechanical cochlear properties which could occur in the contralateral ear following ear surgery, using transient evoked otoacoustic emission (TEOAE) recording. Surgery involved tympanic membrane surgery in 13 cases and middle ear surgery in 16 cases. TEOAEs were recorded and compared for contralateral ears before (day 1: D1) and after (day 2: D2) ear surgery. Two patients failed to show a TEOAE reproductibility > 75%, and were excluded from the study, thus reducing the number of patients to 27. Results were compared to those of a control group of 12 normal hearing subjects, recorded in similar conditions also on day one (D1) and day two (D2). The difference between D1 and D2 was not significant in either group. Pre/postsurgery variations in TEOAE amplitude for the patient group were negatively and significantly correlated with the corresponding preoperative levels in that the greater the presurgical TEOAE level, the larger the decrease in postoperative level. Compared to the variation confidence intervals in the control group, TEOAE amplitude remained stable in 15 patients, increased in four and decreased in eight. These three groups of patients differed only regarding preoperative TEOAE amplitude values, which were significantly greater in the group which presented a decrease in TEOAE amplitude than in the others. Increase in TEOAE amplitude was more frequent after tympanic membrane surgery. On the other hand, TEOAE amplitude decrease was more frequent after middle ear surgery, and is significant compared to the tympanic membrane surgery results. The results show that cochlear micromechanical properties may be reduced in the ear contralateral to surgery and that this decrease depends on the severity of the surgical procedures in the operated ear, such as drilling or opening of the oval window.

Acoustic Stimulation↗

Multiple internal reflections in the cochlea and their effect on DPOAE fine structure.

In recent years, evidence has accumulated in support of a two-source model of distortion product otoacoustic emissions (DPOAEs). According to such models DPOAEs recorded in the ear canal are associated with two separate sources of cochlear origin. It is the interference between the contributions from the two sources that gives rise to the DPOAE fine structure (a pseudoperiodic change in DPOAE level or group delay with frequency). Multiple internal reflections between the base of the cochlea (oval window) and the DP tonotopic place can add additional significant components for certain stimulus conditions and thus modify the DPOAE fine structure. DPOAEs, at frequency increments between 4 and 8 Hz, were recorded at fixed f2/f1 ratios of 1.053, 1.065, 1.08, 1.11, 1.14, 1.18, 1.22, 1.26, 1.30, 1.32, 1.34, and 1.36 from four subjects. The resulting patterns of DPOAE amplitude and group delay (the negative of the slope of phase) revealed several previously unreported patterns in addition to the commonly reported log sine variation with frequency. These observed "exotic" patterns are predicted in computational simulations when multiple internal reflections are included. An inverse FFT algorithm was used to convert DPOAE data from the frequency to the "time" domain. Comparison of data in the time and frequency domains confirmed the occurrence of these "exotic" patterns in conjunction with the presence of multiple internal reflections. Multiple internal reflections were observed more commonly for high primary ratios (f2/f1 > or = 1.3). These results indicate that a full interpretation of the DPOAE level and phase (group delay) must include not only the two generation sources, but also multiple internal reflections.

Acoustic Stimulation↗

Middle ear muscles of the frog.

The anuran middle ear in its complete form includes two skeletal elements, the columella and operculum, each occupying a portion of the oval window of the otic capsule and each provided with a middle ear muscle. The two elements have an interlocking arrangement of a form that makes it possible for these muscles to exercise a high degree of control of sound transmission from tympanic membrane to inner ear receptors. From the anatomical relations it is inferred that the two muscles operate as antagonists so that contraction of the opercular muscle and relaxation of the columellar muscle leave the columella free to move in and out of the oval window in response to sound vibrations, whereas a contraction of the columellar muscle and relaxation of the opercular muscle tend to immobilize the columella and reduce the transmission inward. The frog thus achieves a degree of control of sound reception that probably is unmatched among vertebrate ears. The purpose of the middle ear mechanism is no doubt the protection of the inner ear receptors (the amphibian and basilar papillae) from overstimulation by sounds, including the animal's own cries and the intense clamor produced by a group of frogs calling in chorus.

Animals↗

The facial nerve coursing across the promontory with a persistent stapedial artery.

A case of congenital bilateral conductive deafness is described. Some years ago absence of the oval window was found in the left ear. Exploratory tympanotomy of the right ear revealed a large persistent stapedial artery while the facial nerve took its course from the geniculate ganglion straight down across the promontory anteriorly of the stapedial artery.

Abnormalities, Multiple↗

[Perilymphatic gushers: myths and reality].

The term perilymphatic gusher refers to the escape of inner ear fluid under pressure through the oval window, generally during surgery for otosclerosis. It also appears during cochlear implantation. We reviewed the morphological aspects of the temporal bone of patients with perilymphatic gusher. The cases of three patients with the features of cerebrospinal fluid leaks under pressure cited in the literature are described. Anatomic and pathologic features are discussed in the light of knowledge of molecular genetics.

Adult↗

[Otologic aspects of diving].

Ear diseases are the most common of all occupational diseases of diving. Otitis externa is the most frequent and troublesome infection in divers especially when the environment is humid. During compression, failure to equalize the pressure of the air-filled cavities surrounded by bone (middle ear, sinus) deprives the middle ear (or sinus) of aeration. Middle ear barotrauma is the most common barotrauma encountered in divers while external ear barotrauma (reversed ear) and inner ear barotrauma (with rupture of the round or oval window) are less common. Decompression sickness (Caisson disease) is primarily the result of inert gas bubbles; deafness and vertigo may result if the inner ear is involved. The most dramatic cause of disorientation under water is that due to vertigo. This vertigo is commonly a transient effect due to unequal caloric stimulation of the two labyrinths. The physical examination of the ear and nose necessary for assessment of diving fitness are discussed. A list of ENT contra-indications is presented which mandate temporary or permanent disqualification from diving.

Barotrauma↗

Vein versus tragal perichondrium in stapedotomy.

OBJECTIVE: To assess, in otosclerosis surgery, whether the vein or the tragal perichondrium in stapedotomy with interposition yields the better long-term hearing outcome. STUDY DESIGN: A retrospective chart review of prospectively collected audiometric data of 452 ears. SETTING: Academic tertiary otology-neurotology referral center. PATIENTS: Four hundred fifty-two stapedotomies with interposition were performed in 412 patients (bilateral in 40 patients) by the senior author (R.C.) between 1987 and 1998. A tragal perichondrium graft was used in 314 cases and a vein graft was used in 138 cases as sealing material of the oval window. MAIN OUTCOME MEASURES: Audiometric data were recorded at 4 months, at 1 year, and at 3 years after surgery after American Academy of Otolaryngology-Head and Neck Surgery guidelines, except for thresholds at 3 kHz, which were not available and which were replaced with those at 4 kHz. RESULTS: There were no significant intergroup differences in initial or late postoperative hearing outcome with regard to change in the pure-tone average bone conduction and air-bone gaps, or sensorineural hearing loss. Ears treated with a vein graft showed statistically better postoperative 2-kHz air-bone gap closure (p =0.0157), but the pure-tone average air-bone gap difference was not significant. Postoperative air-bone gap closure to within 10 dB was achieved in 91% of cases in the vein group and in 76% of cases in the perichondrium group. Specific study of the bone conduction level at 4 kHz showed a sensorineural hearing loss greater than 10 dB in 8% of cases in the vein group and in 11% of cases in the perichondrium group. One case of complete sensorineural hearing loss was observed with a tragal perichondrium graft (0.22%). CONCLUSION: These results suggest that the vein should be preferred to the tragal perichondrium in stapedotomy with interposition.

Audiometry, Pure-Tone↗