An exploratory study of imaging diagnostic clues for overhanging facial nerve in ultra-high-resolution CT.

PURPOSE: Overhanging facial nerve (FN) may be challenging in imaging diagnosis. The purpose of the study is to investigate the imaging clues for overhanging FN near the oval window on ultra-high-resolution computed tomography (U-HRCT) images. METHODS: Between October 2020 and August 2021, images of 325 ears (276 patients) were included in the analysis obtained by an experimental U-HRCT scanner. On standard reformatted images, the morphology of FN was evaluated and its position was quantitatively measured using the following indices: protrusion ratio (PR), protruding angle (A), position of FN (P-FN), distance between FN and stapes (D-S), and distance between FN and anterior and posterior crura of stapes (D-AC and D-PC). According to the FN morphology in imaging, images were divided into overhanging FN group and non-overhanging FN group. Binary univariate logistic regression analysis was used to identify the imaging indices independently associated with overhanging FN. RESULTS: Overhanging FN was found in 66 ears (20.3%), which manifested as downwards protrusion of either local segment (61 ears, 61/66) or the entire course near the oval window (5 ears, 5/66). D-AC [odds ratio: 0.063, 95% CI 0.012-0.334, P = 0.001) and D-PC (odds ratio: 0.008, 95% CI 0.001-0.050, P = 0.000) were identified as independent predictors of FN overhang (area under the curve: 0.828 and 0.865, respectively). CONCLUSION: Abnormal morphology of the lower margin of FN, D-AC and D-PC on U-HRCT images provide valuable diagnostic clues for FN overhang.

Comparison of different oval window sealing materials in stapes surgery: systematic review and meta-analysis.

OBJECTIVE: To compare the efficacy and safety characteristics of different materials used for oval window sealing during stapedotomy. METHODS: A systematic review was conducted according to the PRISMA guidelines. Published international English literature from January 1, 2000 to December 2021 was screened, checking for studies that compared different materials utilization in patients undergoing stapedotomy surgery for otosclerosis or congenital stapes fixation. Data related to the efficacy and safety of each material were extracted. The primary outcome measure was the air-bone gap (ABG) closure after surgical intervention. RESULTS: Six studies were included in the metanalysis. Because of the heterogeneity of the treatments adopted, we assessed the use of the fat compared to all other treatments, and the use of the gelfoam compared to all other treatments. In the former analysis (fat vs others) we did not identify differences in ABG closure between the groups (p = 0.74), with a low heterogeneity of the results (I2 = 28.36%; Hedge's g = 0.04, 95% CI - 0.19 0.27); similarly, we did not identify differences between the use of gelfoam and other treatments (p = 0.97), with a low heterogeneity of the results (I2 = 28.91%; Hedge's g = 0.00, 95% CI - 0.20 0.21). CONCLUSIONS: Numerous options are available for oval window sealing during stapedotomy, with acceptable safety and effectiveness profiles. Based on the current data, no definitive recommendation can be made regarding the choice of one material over another, and the convenience of sealing over no sealing at all.

Taste impairment after endoscopic stapes surgery: Do anatomic variability of chorda tympani and surgical technique matter? : Post-operative dysgeusia after EStS.

PURPOSE: To investigate how the anatomical configuration of the oval window region (OWR) influences the management of the chorda tympani (ChT) and the curetting of adjacent bony structures, in a setting of patients undergoing endoscopic stapes surgery (EStS); to assess the incidence of early and late post-operative dysgeusia and to identify anatomical and surgical factors influencing taste function after EStS. METHODS: Surgical video recordings of 48 patients undergoing EStS for otosclerosis between January 2019 and July 2020 were retrospectively revised, to classify the anatomical variability of selected middle ear structures and the management strategies for the ChT. Clinical records of included patients were reviewed for subjective early and late post-operative taste impairment using a 5-point Likert-scale. RESULTS: The most common configuration of the OWR was type III. The extension of the bony curettage resulted inversely proportional to the exposure of the OWR. The long-term rate of preserved post-operative taste function was 85%. Displacement of the ChT was necessary in 43/48 cases (90%), mostly medially (36/48, 75%). CONCLUSION: Bone curetting during EStS does not correlate with post-operative taste impairment. Despite 100% ChT preservation rate, dysgeusia may occur in a minority of patients, with no apparent relationship to anatomical variability or intraoperative management of the ChT. The use of CO2 laser could have a role in increasing the risk of post-operative dysgeusia after EStS.

Anatomic features of the fetal round and oval windows, and their relations with the tympanic nerve.

OBJECTIVE: The study aimed to examine morphometric properties of the round window (RW) and oval window (OW) and to show their relation with the tympanic nerve (the Jacobson's nerve, JN) in human fetuses from the otologic surgeon's perspective. METHODS: Thirty temporal bones of 15 fetal cadavers (8 males, 7 females) aged with 24.40 ± 3.71 weeks were included in the study. The height, width and surface area of the RW and OW and also distance from the JN to the OW and RW were measured. RESULTS: The height, width and surface area of the RW in this work were measured as 1.48 ± 0.25 mm, 1.57 ± 0.37 mm, and 2.05 ± 0.69 mm2, respectively. The RW was detected as round-shaped (8 cases, 26.7%), oval-shaped (15 cases, 50%), and dome-shaped (7 cases, 23.3%). The height, width and surface area of the OW were measured as 1.42 ± 0.26 mm, 2.90 ± 0.44 mm, and 3.63 ± 0.74 mm2, respectively. The OW was observed as oval-shaped (15 cases, 50%), kidney-shaped (10 cases, 33.3%), D-shaped (4 cases, 13.3%), and trapezoid-shaped (1 case, 3.3%). The JN was found 1.21 ± 0.60 and 1.18 ± 0.54 mm away from the RW and OW, respectively. CONCLUSION: This study containing morphological data about the shapes, diameters and area of the RW and OW may be useful to predict surgical difficulty, and to select implants of suitable size preoperatively for the windows. Knowing the relationship between the JN and the windows can be helpful to avoid iatrogenic injuries of the nerve.

Anatomic variability of oval window as pertaining to stapes surgery.

PURPOSE: The purpose of the study is to study the details of dimensions and shape of oval window in different age groups, sides and genders and their clinical implications. The oval window is a key structure while performing surgeries in relation to stapes. An intricate knowledge of the shape and size of the oval window is important for the reconstruction and fitting of cartilage compatible with the native shape of the oval window. METHODS: Sixty normal wet cadaveric temporal bones of known age; gender and side were micro-dissected. The maximum height and width of the oval window was measured. The shape of the oval window was noticed. RESULTS: The mean value for maximum height and width of the oval window was 1.31 ± 0.28 mm and 2.67 ± 0.42 mm, respectively. The height and width of the oval window ranged between 1 mm and 1.5 mm and 2 mm and 3 mm in majority of the cases. he oval window was found to be oval shaped in 53.3% cases, other shapes such as kidney, D shape, rectangular or trapezoidal were also observed. CONCLUSIONS: The refined morphometric information of the oval window will help in preoperative assessment and surgical planning of various oval window-related surgical procedures. The knowledge may also help in designing and selecting proper cartilage shoe for the best outcome. Narrow oval window may cause procedural complications and surgeon discomfort in various stapes surgeries.

The role of endoscopic stapes surgery in difficult oval window niche anatomy.

PURPOSE: The surgical treatment of otosclerosis can be challenging in case of anatomical abnormalities or variations of the oval window niche (OWN) area, as in very narrow OWN or in an overhanging facial nerve. The aim of the present study was to explore the role of endoscopic stapes surgery in cases with difficult OWN anatomy. METHODS: Patients undergoing endoscopic stapes surgery from 2008 to 2017, which fulfilled the CT scan criteria for a "difficult" anatomical condition, according to the measurements and cut-off values defined in the literature, were retrospectively selected. The intraoperative endoscopic view of the anatomical details and surgical difficulties were analysed through the review of the operative videos. Finally, a statistical analysis of the relationship between endoscopic visualization of anatomical details and radiological measurements was carried out. RESULTS: Eighteen out of 205 patients (8.7%) were included in the study. The 94.4% of patients obtained an optimal endoscopic exposure and visualization of all the anatomical details considered in the study, during each step of stapes surgery. The OWN measurements (width, depth and facial-promontory angle) did not affect significantly the endoscopic surgical exposure of the footplate or any of the other anatomical details. CONCLUSIONS: The anatomic features of the oval window area which reduce the visualization in microscopic surgery, did not affect the surgical exposure in endoscopic stapes surgery. Patients having a difficult anatomy of the OWN can be treated safely with the endoscopic approach. In the case of a predicted "difficult anatomy", the endoscopic approach can be considered a viable option.

The role of explorative tympanotomy in patients with sudden sensorineural hearing loss with and without perilymphatic fistula.

PURPOSE: The purpose of this study was to describe the role of explorative tympanotomy in patients with Profound Sudden Sensorineural Hearing Loss (SSNHL) without clinical evidence of perilymphatic or labyrinthine fistula and to compare intraoperative findings with the postoperative hearing outcome. STUDY DESIGN: Retrospective study of all patients diagnosed with SSNHL who underwent explorative tympanotomy between 2002 and 2005. SETTINGS: Tertiary care university-affiliated hospital. SUBJECTS AND METHODS: Eighty-two patients were diagnosed with unilateral profound SSNHL and underwent tympanotomy with sealing of the round and oval windows. Values of pure tone audiograms and percentage hearing loss of patients with and without intraoperative diagnosed perilymphatic fistula (PLF) were compared and analyzed. RESULTS: PLF was diagnosed in 28% cases intraoperatively. In most cases, hearing improved significantly after surgery. Interestingly, patients with PLF had a 2.4 times greater decrease of percentage hearing loss compared to patients without PLF. CONCLUSIONS: Explorative tympanotomy seems to be useful in patients with profound SSNHL. Patients with PLF benefit more from the surgical procedure and have better outcome than patients without PLF.

Comparison of Alternative Coupling Methods of the Vibrant Soundbridge Floating Mass Transducer.

The active middle ear implant Vibrant Soundbridge© provides a variety of coupling modalities of the floating mass transducer (FMT) to various structures of the ossicular chain and the round window. A retrospective analysis was performed on 125 subjects (n = 137 ears) (1) to compare the efficacy of the different FMT coupling modalities with increasing degree of hearing loss, (2) to compare the performance in speech outcome and the effective gain between the coupling types, and (3) to evaluate the risk of additional hearing loss of each coupling procedure. The patients were grouped according to their type of FMT coupling into incus vibroplasty (incus group, n = 59), round window vibroplasty with coupler (RWC group, n = 23), round window vibroplasty without coupler (RW group, n = 22), and oval window vibroplasty with coupler (OWC group, n = 33). For each coupling group, pre- and postoperative thresholds, the results of the Freiburg monosyllable test at 65 dB SPL, and the effective gain across frequencies (0.5-6 kHz) were evaluated. A logistic regression function was used to describe the relationship between word recognition scores (WRS, in % correct) and the mean bone conduction (BC) hearing loss. The surgical procedure had no clinically relevant effect on BC thresholds of patients in each coupling group. The BC pure tone average (PTA4) for 50% WRS predicted by the model function was similar for the incus (48.2 dB nHL), RW (47.8 dB nHL), and OWC (49.0 dB nHL) groups, but higher for the RWC group (67.9 dB nHL). However, the median WRS was 80% or better with no significant differences in speech perception between coupling types (Kruskal-Wallis test, p = 0.229). The effective gain shows an advantage for the incus coupling between 0.5 and 2 kHz over the other coupling types. The performance of the FMT coupling modalities is equally good for patients with a mild-to-moderate hearing loss, but the efficacy of coupling types differs for patients with greater hearing loss (>48 dB BC HL).

Congenital malformation of the oval window: experience of radiologic diagnosis and surgical technique.

The aim of this study was to introduce and discuss the method of preoperative radiological diagnosis to the congenital absence or atresia of the oval window (OW), and the method of surgical treatment. From July 2010 through August 2014, patients with normal external canal and tympanic membrane but conductive hearing loss underwent high resolution CT scan (HRCT). The multi-planar reformation (MPR), a post-processing protocol, was used. The patients with diagnosis of OW atresia and malformed stapes preoperatively underwent surgical treatment. The vestibular drilled-out and promontory drilled-out technique was used to reconstruct the ossicular chain. In the preoperative radiological diagnosis, six patients (ears) were noted to have congenital absence or atresia of the oval window with malformed facial nerve (class 4) and two patients (ears) were found to have footplate fixation (class 2). In the surgical treatment of eight ears, the malformed structure was identified and the ossicular chain reconstruction was made in six ears. The coronal HRCT CT imaging and the MPR post-processing technique can provide us practical and definite information for surgical treatment, especially in the discrimination of OW atresia and the fixed stapedal footplate. The promontory drill-out technique, fenestration in the bottom of the basal turn, provides us a new method in the hearing reconstruction when the area of OW was fully covered by malformed facial nerve. This technique was first reported in the literature.

Histopathological Patterns of Otosclerosis Progression: Exploring Otic Capsule and Round Window Involvement.

OBJECTIVES: Obliteration of the round window (RW) in cases of otosclerosis presents a significant clinical challenge due to its association with more severe hearing loss and a poorer prognosis for functional recovery after stapes surgery. The objective is to assess and characterize the occurrence of RW involvement in otosclerosis cases and to identify patterns of disease progression that may indicate a potential for RW obliteration. METHODS: We selected archival temporal bones from donors with otosclerosis. We evaluated the degree of RW obliteration using a semi-quantitative scale and the location of the foci within the temporal bone, and whether the foci were continuous or isolated. RESULTS: Most of the foci were located anteriorly to the oval window (89.2%), while RW area involvement was seen in 26.9% of the ears. In cases with fenestral foci, 68.1% directly involved and/or fixed the footplate. Among donors with bilateral otosclerosis, foci affected both ears in a similar pattern in 64.2%. Among donors with RW involvement, ones with continuous, large lesions that extended from the oval window associated with complete RW obliteration, while ones with smaller degrees of obliteration had solitary foci scattered within the otic capsule. CONCLUSION: Our results demonstrate a high rate of RW involvement in cases of otosclerosis. Ears with continuous lesions extending from the oval window region to the RW area were more likely to present with complete RW obliteration. These results provide insights that could lead to better prognostic assessment of patients with otosclerosis in the future. LEVEL OF EVIDENCE: N/A Laryngoscope, 2024.

Suspicion and Treatment of Perilymphatic Fistula: A Prospective Clinical Study.

Background: Since the discovery of the perilymphatic fistula (PLF), the diagnosis and treatment remain controversial. If successfully recognized, the PLF is surgically repairable with an obliteration of the fistula site. Successful treatment has a major impact on patient's quality of life with an improvement in their audiological and vestibular symptoms. Objective: To prospectively investigate patients' clinical and audiological evolution with PLF suspicion after middle ear exploration and obliteration of the round and oval window. Study Design: Prospective comparative study. Setting: Tertiary care center. Methods: Patients were divided into two groups: Group I consisted of patients where no PLF had been identified intraoperatively at the oval and/or at the round window, and Group II consisted of patients where a fistula had been visualized. Patient assessment was a combination of past medical history, the presence of any risk factors, cochlear and vestibular symptoms, a physical examination, temporal bone imaging, audiograms, and a videonystagmogram (VNG). Results: A total of 98 patients were divided into two groups: 62 in Group I and 36 in Group II. A statistically significant difference regarding gender was observed in Group II (83.3% of males vs. 16.7% of females, p = 0.008). A total of 14 cases (4 and 10 in Groups I and II, respectively) were operated for a recurrent PLF. Fat graft material was used in the majority of their previous surgery; however, no difference was found when comparing fat to other materials. In addition, no statistically significant difference was noted between Groups I and II concerning predisposing factors, imaging, VNG, symptom evolution, or a physical exam before the surgery and at 12 months post-operative. However, both groups showed statistically significant hearing and vestibular improvement. On the other hand, the air conduction (AC) and bone conduction (BC) at each frequency were not statistically different between the two groups before surgery but showed statistically significant improvement at 12 months post-operatively, especially for the BC at the frequencies 250 (p = 0.02), 500 (p = 0.0008), and 1000 Hz (p = 0.04). Conclusions: Whenever you suspect a perilymphatic fistula, do not hesitate to explore middle ear and do window obliterations using a tragal perichondrium material. Our data showed that cochlear and vestibular symptoms improved whether a fistula had been identified or not.

Effectiveness of active middle ear implant placement methods in pathological conditions: basilar membrane vibration simulation.

Active middle ear implants (AMEI) amplify mechanical vibrations in the middle ear and transmit them to the cochlea. The AMEI includes a floating mass transducer (FMT) that can be placed using two different surgical approaches: "oval window (OW) vibroplasty" and "round window (RW) vibroplasty." The OW and RW are windows located on the cochlea. Normally, sound stimulus is transmitted from the middle ear to cochlea via the OW. RW vibroplasty has been suggested as an alternative method due to the difficulty of applying OW vibroplasty in patients with ossicle dysfunction. Several reports compare the advantages of each approach through pre and postoperative hearing tests. However, quantitatively assessing the treatment effect is challenging due to individual differences in pathologies. This study investigates the vibration transmission efficiency of each surgical approach using a finite-element model of the human cochlea. Vibration of the basilar membrane (BM) of the cochlea is simulated by applying the stimulus through the OW or RW. Pathological conditions, such as impaired stapes mobility, are simulated by increasing the stiffness of the stapedial annular ligament. RW closure due to chronic middle ear diseases is a common clinical occurrence and is simulated by increasing the stiffness of the RW membrane in the model. The results show that the vibration amplitude of the BM is larger when the stimulus is applied to the RW compared to the OW, except for cases of RW membrane ossification. The difference in these amplitudes is particularly significant when stapedial mobility is limited. These results suggest that RW vibroplasty would be advantageous, especially in cases of accompanying stapedial mobility impairment. Additionally, it is suggested that transitioning to OW vibroplasty could still ensure a sufficient level of vibratory transmission efficiency when placing the FMT on the RW membrane is difficult due to anatomical problems in the tympanic cavity or confirmed severe pathological conditions around the RW.

Bilateral Congenital Agenesis of Stapes and Oval Window in Two Members of a Family (Brother and Sister).

Congenital agenesis of the stapes and the oval window is rare. Congenital stapedial agenesis (CSA) may be recognized preoperatively in the presence of conductive hearing loss. The principal radiological imaging approach of the temporal bone, computed tomography (CT), can be used to diagnose CSA. Our 17-year-old male patient (case A) had long-term hearing loss which was getting worse. A temporal bone CT scan revealed the absence of the stapes and the oval window on both sides and an abnormal position of the facial nerve. No anomalies were detected in the external ear structures. Explorative right ear tympanotomy revealed an abnormal inferior course and dehiscence of the facial nerve. The oval window and stapedial structures were absent. Patients were evaluated for continued hearing aid use or bone-anchored hearing aid implantation. Similar CT imaging and clinical abnormalities were seen in his 16-year-old sister (case B). They did not have any other siblings and neither of their parents nor any of their relatives had hearing loss. This report presents the CT scans of the two siblings with mixed hearing loss (mainly conductive) and the perioperative image of the first case. A genetic study may help explain the etiopathogenesis since both cases had similar clinical and imaging findings.

Facial canal dehiscence in patients undergoing surgery for chronic otitis media: analysis of 850 patients.

ntroductionIn all otologic surgeries, the facial nerve can be considered the most important structure that must be protected. The surgical damage risk of the facial nerve will be increased in presence of facial canal dehiscence (FCD).AimIn this study, we aimed to evaluate the FCD and its associated situations in patients with chronic otitis media undergoing mastoidectomy.Materials and Methods850 patients who performed ear surgery were reviewed. Patients who did not perform mastoidectomy were excluded. In patients, the ratios, localization of FCD, and association of facial canal dehiscence with cholesteatoma were researched. Association between FCD and closed-cavity tympanomastoidectomy, open-cavity tympanomastoidectomy, and radical mastoidectomy procedures, and also an association between FCD and primary or revision surgery was evaluated. ResultsFacial canal dehiscence was found in 8.4% of patients. The relationship between dehiscence and cholesteatoma was found significant (p<0.001). In the comparison of radical mastoidectomy and closed-cavity tympanomastoidectomy, dehiscence was higher in the radical mastoidectomy group (p<0.03). In revision cases, dehiscence was seen more frequently (p<0.003). FCD incidence was higher in adult patients than in pediatric patients (p<0.001). Twenty of 468 patients who were operated on for cholesteatoma had congenital cholesteatoma. ConclusionFacial canal dehiscence can be seen especially in cases with cholesteatoma and when performing radical mastoidectomy and revision surgeries. Therefore, a detailed evaluation of the status of facial nerve and determination of situations in which occurrence of FCD is more likely both preoperatively and intraoperatively will minimalize potential complications.Keywords: Cholesteatoma, tympanic, radical mastoidectomy, oval window, tympanomastoidectomy.

Fetal development and growth of the fissula ante fenestram in the human ear.

Since the fissula ante fenestram (FAF) is considered as a focus of otosclerotic lesion and a route of perilymph leakage, there are few description of prenatal development of the cartilaginous canal passing though the cochlear wall. We examined the sagittal and frontal histological sections of the ear from 32 human fetuses at 8-37 weeks of gestational age. At 8-12 weeks, in the immediately anterior side of a connection between the cochlear and canalicular parts of the otic capsule cartilage, the FAF appeared as a tear of a cartilage between the basal and second turns of the cochlea. The tear became a slit opening to the scala vestibuli. At 13-15 weeks, the FAF, less than 1.2 mm in length, had the anterosuperior and postero-inferior apertures: the former was near the geniculate ganglion and became closed after 15 weeks, while the latter approached the oval window. Third trimester fetuses, the FAF, 1.5-2.0 mm in length, consistently carried a single, postero-inferior aperture extending along the anterior margin of the oval window and it contained no definite epithelium and vessel. Although it was endochondral ossification, there was no clear zonation in cartilage cells of the FAF. A mechanical stress during three-dimensional coiling of the cochlear ducts seemed to provide the FAF. After the FAF was established, the stapes footplate might use a part of the inferior aperture for the syndesmosis. A specific ossification was seen in the FAF, but it might rarely cause the pathological syndesmosis.

Efficient Delivery of Adeno-Associated Virus into Inner Ear In Vivo Through Trans-Stapes Route in Adult Guinea Pig.

Adeno-associated virus (AAV) are potent vectors to achieve treatment against hearing loss resulting from genetic defects. However, the effects of delivery routes and the corresponding transduction efficiencies for clinical applications remain elusive. In this study, we screened AAV vectors of three serotypes (AAV 8 and 9 and Anc80L65) into the inner ears of adult normal guinea pigs through trans-stapes (oval window) and trans-round window delivery routes in vivo. Trans-stapes route is akin to stape surgeries in humans. Then, auditory brainstem response (ABR) measurements were conducted to evaluate postoperative hearing, and inner ear tissues were harvested for transduction efficiency analysis. Results showed that AAV8 targeted partial inner hair cells (IHCs) in cochlear basal turn; AAV9 targeted IHCs in cochlear basal and second turn, also a part of vestibular hair cells (VHCs). In contrast, Anc80L65 contributed to green fluorescent proteins (GFP) signals of 80 - 95% IHCs and 67 - 91% outer hair cells (OHCs), as well as 69% VHCs through the trans-round window route, with 15-20 decibel (dB) ABR threshold shifts. And, through the trans-stapes (oval window) route, there were 71 - 90% IHCs and 42 - 81% OHCs, along with 64% VHCs demonstrating GFP positive, and the ABR threshold shifts were within 10 dB. This study revealed AAV could be efficiently delivered into mammalian inner ear cells in vivo through the trans-stapes (oval window) route with postoperative hearing preservation, and both delivery routes showed promise of virus-based clinical translation of hearing impairment treatment.

Bone-conduction hearing aid is effective in congenital oval window atresia.

BACKGROUND: Implantable bone-conduction hearing aids (BCHA) are effective in patients with congenital ear malformations.However, there is no large sample study to verify the efficacy of Bonebridge in patients with congenital oval window atresia. OBJECTIVES: To investigate efficiency of implantable bone-conduction hearing aids in Mandarin-speaking patients with congenital oval window atresia. MATERIAL AND METHODS: We retrospectively analyzed 15 patients, who were confirmed with either unilateral or bilateral congenital oval window atresia by temporal bone CT. All patients were implanted with a bone-conduction hearing device between July 2016 and July 2019 at Beijing Tongren Hospital, Capital Medical University. Pure tone audiometry (PTA), air-bone gap (ABG), speech discrimination scores (SDSs), and hearing thresholds were performed. RESULTS: Postoperative complications including facial paralysis were particularly rare. Unaided mean sound field threshold was 62.2 ± 10.5 dBHL and that with implantable bone-conduction hearing aids was 39.1 ± 13.2 dBHL (p < 0.01). The mean speech discrimination scores improved greatly (p < 0.01), specifically with regard to sentence and disyllabic words. CONCLUSIONS: Patients with congenital oval window atresia often show moderate to severe conductive hearing loss. Implantable bone-conduction hearing aids are considerably safe and stable for hearing rehabilitation. It is a novel treatment modality for Mandarin-speaking patients with congenital oval window atresia.

The design of a lumped parameter model considering the stimulus path of round window.

BACKGROUND: Sound normally enters the ear canal, passes through the middle ear, and stimulates the cochlea through the oval window. Alternatively, the cochlea can be stimulated in a reverse manner, namely round window stimulation. The reverse stimulation is not well understood, partly because in classic lumped-parameter models the path of reverse drive during the round window stimulation is usually not considered. OBJECTIVE: The study goal is to gain a better understanding of the hearing mechanism during round window stimulation. METHODS: A piezo actuator was coupled to the oval and round window of the guinea pigs. The auditory brainstem response produced by the forward and reverse stimulation at four frequencies was recorded. RESULTS: The results show that the input voltage of the actuator required at the hearing threshold in the round window drive was higher than that in the oval window drive. In order to understand the data, we designed a lumped-parameter cochlear model that can simulate both forward and reverse drive. The model-predicted results were consistent with the experimental results. CONCLUSIONS: The response of the auditory system to stimulus of oval window and round window was quantified through animal experimentation, and guinea pigs were used as experimental animals. When the same stimulus was applied to the oval window and round window of the cochlea, the ABR signals were compared. A lumped parameter model was designed to incorporate the sound transmission paths in both oval and round window stimulation. The simulated results are consistent with those of animal experiments. This model will be useful in understanding the inner-ear response in round window.

Management of stapes footplate fistula in inner ear malformations.

BACKGROUND: Certain inner ear malformations have stapes footplate fistula which may cause meningitis during otitis media. This may result in fatality. It is the responsibility of the otolaryngologist to diagnose and treat the condition to prevent further attacks of meningitis. MATERIALS AND METHODS: Surgical findings of the 17 patients who have inner ear malformations with oval window fistula were retrospectively analyzed. Inner ear malformations were classified according to Sennaroglu classification. Different stages of stapes footplate fistula are classified. FINDINGS: Seventeen patients had spontaneous stapes footplate fistula at the oval window. No patient had spontaneous leakage at the round window site. Proper sealing of the leakage area with fascia in a dumbbell fashion is mandatory. Keeping the stapes in place and lumbar drainage are the two most important factors in the successful management of fistula. Particularly important is the simultaneous fistula repair and cochlear implantation where combined postauricular-transcanal approach provides the best method. Vaccination is important but not sufficient to prevent meningitis in inner ear malformations unless repair of the fistula is performed. CONCLUSION: If the patient has a history of meningitis in the presence of inner ear malformation, particular attention should be given to oval window area to look for an opacity, cyst or a leaking lesion at the stapes footplate. Immediate surgical exploration and repair of the leak is mandatory to prevent further attacks of meningitis. Surgeon should not leave the operation without fully controlling the leak.

Cochlear implant surgery through oval window: A novel approach in a child with facial nerve aberration.

Cochlear implantation is safe for simple case presentations. However, facial nerve (FN) aberrations may impede insertion of the electrode through a round window and increase the risk of iatrogenic FN injury. We developed a novel method of cochlear implantation, a present the case of a child with FN aberrations. Inferior displacement of a horizontal segment of FN lay on the surface of th e promontory, obscuring the round window. The oval window was used and the electrode successfully inserted. No postoperative complications occurred, and significant improvement in speech perception was achieved. This novel approach is suitable for patients with FN aberrations.