Evaluation Deviation of Round-Window Stimulation Based on Basilar Membrane Response / 医用生物力学

Objective To study the accuracy of traditional basilar membrane displacement evaluation criteria for evaluating hearing compensation performance of round window-stimulated middle ear implant, so as to provide the theoretical basis for performance evaluation of round window-stimulated middle ear implant. Methods An acoustic microscopic finite element model of cochlea was constructed based on experimental data of the cochlea geometry. Reliability of this model was verified by comparison with experimental measurement values of inner hair cell, outer hair cell, tectorial membrane displacement. Based on this model, the displacement of basilar membrane and the stereocilia shear displacement of inner hair cells under forward stimulation and round-window stimulation were comparatively analyzed. Using the stereocilia shear displacement of inner hair cells as the criterion for sense of sound, the equivalent sound pressure level (SPL) deviation under round-window stimulation was studied when using traditional basilar membrane displacement as evaluation criterion. Results At 5 kHz characteristic frequency of the studied slice of cochlea, under sound pressures with the same amplitude, the displacement of basilar membrane and the stereocilia shear displacement of inner hair cells under round-window stimulation were lower than that under forward stimulation. Conclusions Under forward stimulation, the inner hair cells were more excited and the performance for sense of sound was better than that under round-window stimulation. Concurrently, using the displacement of basilar membrane under forward stimulation as the criterion of hearing compensation performance would overestimate hearing compensation performance of middle ear implant under round-window stimulation; but the deviation was relatively small, which was a relatively reliable evaluation method.

Anatomical Study of the Facial Recess with Implications in Round Window Visibility for Cochlear Implantation: Personal Observations and Review of the Literature

Abstract Introduction Posterior tympanotomy through facial recess (FR) is the conventional and most preferred approach to facilitate cochlear implantation, especially when the electrode is inserted through the round window. The complications of the FR approach can be minimized by proper understanding of the anatomy of the FR. Objective The present study was undertaken to assess the various parameters of FR and round window visibility, which may be of relevance for cochlear implant surgery. Methods Thirty-five normal wet human cadaveric temporal bones were studied by dissection for anatomy of FR and posterior tympanum. Photographs were taken with an 18megapixels digital camera, which were then imported to a computer to determine various parameters. Results The mean distance from the take-off point/crotch of the chorda tympani nerve (CTN) to the stylomastoid foramen was 4.08 ± 0.8 mm(range of 2.06 - 5.5mm). The variations in the course of the CTN included origin at the level of the lateral semicircular canal. Themean chorda-facial angle in our study was 26.91° ± 1.19°, with a range of 25° to 28.69°. The mean FR length ranged between 9.4 mm and 18.56 mm (mean of 12.41 ± 2.91mm) and varied with the origin of the CTN and pneumatization of temporal bone. The average maximum width of the FR was 2.93 ± 0.4 mm (range 2.24-3.45 mm) and the mean width of the FR at the level of the round window was 2.65 ± 0.41 mm. Conclusion The FR approach provides good access to the round windowmembrane in all cases. In some cases, table adjustment is required.

Applied anatomy of round window and adjacent structures of tympanum related to cochlear implantation / Anatomia aplicada da janela redonda e estruturas adjacentes relacionadas ao implante coclear

Abstract Introduction: Various aspects of the round window anatomy and anatomy of posterior tympanum have relevant implications for designing cochlear implant electrodes and visualizing the round window through facial recess. Preoperative information about possible anatomical variations of the round window and its relationships to the adjacent neurovascular structures can help reduce complications in cochlear implant surgery. Objective: The present study was undertaken to assess the common variations in round window anatomy and the relationships to structures of the tympanum that may be relevant for cochlear implant surgery. Methods: Thirty-five normal wet human cadaveric temporal bones were studied by dissection for anatomy of round window and its relation to facial nerve, carotid canal, jugular fossa and other structures of posterior tympanum. The dissected bones were photographed by a digital camera of 18 megapixels, which were then imported to a computer to determine various parameters using ScopyDoc 8.0.0.22 version software, after proper calibration and at 1× magnification. Results: When the round window niche is placed posteriorly and inferiorly, the distance between round window and vertical facial nerve decreases, whereas that with horizontal facial nerve increases. In such cases, the distance between oval window and round window also increases. Maximum height of the round window in our study ranged from 0.51-1.27 mm (mean of 0.69 ± 0.25 mm). Maximum width of round window ranged from 0.51 to 2.04 mm (mean of 1.16 ± 0.47 mm). Average minimum distance between round window and carotid canal was 3.71 ± 0.88 mm (range of 2.79-5.34 mm) and that between round window and jugular fossa was 2.47 ± 0.9 mm (range of 1.24-4.3 mm). Conclusion: The distances from the round window to the oval window and facial nerve are important parameters in identifying a difficult round window niche. Modification of the electrode may be a better option than drilling off the round window margins for insertion of cochlear implant electrodes.

Resumo Introdução: Vários aspectos da anatomia da janela redonda e da anatomia da caixa timpânica posterior são relevantes, devido a suas implicações no desenho dos eletrodos para o implante coclear e na visibilidade da janela redonda através do recesso facial. Informações prévias sobre possíveis variações anatômicas da janela redonda e suas relações com as estruturas neurovasculares adjacentes podem ajudar a reduzir as complicações dessa cirurgia. Objetivo: O presente estudo foi realizado para avaliar as diversas variações da anatomia da janela redonda e sua relação com as estruturas adjacentes, o que pode ser relevante para a cirurgia de implante coclear. Método: Trinta e cinco ossos temporais normais de cadáveres humanos frescos foram dissecados para avaliação da anatomia da janela redonda e sua relação com o nervo facial, canal carotídeo, fossa jugular e outras estruturas da caixa timpânica posterior. Os ossos dissecados foram fotografados com uma câmera digital de 18 megapixels e as imagens importadas para um computador para determinar diversos parâmetros, utilizando-se o software ScopyDoc versão 8.0.0.22, após a calibração adequada e com ampliação de 1×. Resultados: Quando o nicho da janela redonda se encontra posicionado posteriormente e inferiormente, a distância entre a janela redonda e o nervo facial vertical diminui, enquanto aquela com o nervo facial horizontal aumenta. Em tais casos, a distância entre a janela oval e a janela redonda também aumenta. A altura máxima da janela redonda em nosso estudo variou de 0,51 a 1,27 mm (média de 0,69 ± 0,25 mm). A largura máxima da janela redonda variou de 0,51 a 2,04 mm (média de 1,16 a 0,47 mm). A distância mínima média entre a janela redonda e o canal carotídeo foi de 3,71 ± 0,88 mm (variação de 2,79 a 5,34 mm) e entre a janela redonda e a fossa jugular, em nosso estudo, foi de 2,47 ± 0,9 mm (variação de 1,24 ± 4,3 mm). Conclusão: A distância da janela redonda a partir da janela oval e do nervo facial são parâmetros importantes para a identificação do difícil nicho da janela redonda. A modificação do desenho do eletrodo pode ser uma opção melhor do que o broqueamento das margens da janela redonda para a inserção dos eletrodos no implante coclear.

Hearing Outcome Following Canal Wall Down Mastoidectomy With And Without Mastoid Cavity Obliteration And Round Window Shielding- A Comparative Observational Study

INTRODUCTION- The accurate diagnosis of disease tissue is elementary to the precise diagnosis and proper management of central nervous system lesions. Although histopathology is gold standard, in neurosurgical practice intraoperative cytological diagnosis is now well established and emerge as a dependable standalone diagnostic tool. The rapidity at which sufficient preliminary information for optimal surgery is provided to neurosurgeons, help him take crucial decision regarding patients management. Overall soft nature of CNS lesions ,best suited for smear cytology, which in fact is the major restriction while performing intraoperative Frozen section consultation. So the present study was done to assess the utility of squash cytology in intraoperative diagnosis of CNS lesions. MATERIALAND METHODS-In this prospective study 142 patients with clinical diagnosis of CNS lesions were studied. Patients clinical and radio imaging findings were taken into account while evaluating squash smear preparation. Squash diagnosis was latter correlated with final histopathological diagnosis . RESULTS– Out of 142 cases, cytological diagnosis was offered in 136 cases. In 6 cases no opinion was possible on cytology. Cyto-histological correlation was seen in 127 out of 136 cases, 9 cases remained discordant. Thus overall diagnostic accuracy of squash cytology in intraoperative diagnosis of CNS lesions in our study was 93.38%. CONCLUSION- Intraoperative squash cytology is easy ,rapid, reliable and cost-effective technique for neurosurgical consultation with fairly high accuracy. Knowledge of clinicoradiological details help to further improve the diagnostic accuracy

Numerical Analysis on Sound Compensation Performance of Round Window Stimulation in Middle Ear Malformation / 医用生物力学

Objective To study the influence of middle ear malformation on the performance of round window stimulation, so as to provide references for optimization of the round window stimulation middle ear implant. Methods The finite element model of human ear including an asymmetrical two-cavity non-helical cochlea was constructed and compared with experimental data to verify reliability of the model. Based on this model, the effects of three kinds of middle ear malformation, i.e., ossicular chain fixation, ossicular chain fusion and ossicular defect on round window stimulation were simulated by changing material properties of the corresponding tissues. Results The middle ear malformation mainly affected the low-frequency performance of round window stimulation. The ossicular chain fixation and the ossicular chain fusion had a deteriorating effect on round window stimulation. The stapes fixation had the greatest effect on the performance of round window stimulation, with the reduction as high as 47.93 dB. Ossicles defects could improve the performance of round window stimulation, with the maximum increment of 6.24 dB. Conclusions The middle ear malformation had an effect on the low frequency performance of round window stimulation. It is necessary to specifically increase output of the actuator when implanting the round window stimulation middle ear implant.

Numerical analysis of the influence of otitis media on the hearing compensation performance of round-window stimulation / 生物医学工程学杂志

In order to study the influence of tympanic membrane lesion and ossicular erosion caused by otitis media on the hearing compensation performance of round-window stimulation, a human ear finite element model including cochlear asymmetric structure was established by computed tomography (CT) technique and reverse engineering technique. The reliability of the model was verified by comparing with the published experimental data. Based on this model, the tympanic membrane lesion and ossicular erosion caused by otitis media were simulated by changing the corresponding tissue structure. Besides, these simulated diseases' effects on the round-window stimulation were studied by comparing the corresponding basilar-membrane's displacement at the frequency-dependent characteristic position. The results show that the thickening and the hardening of the tympanic membrane mainly deteriorated the hearing compensation performance of round-window stimulation in the low frequency; tympanic membrane perforation and the minor erosion of ossicle with ossicular chain connected slightly effected the hearing compensation performance of round-window stimulation. Whereas, different from the influence of the aforementioned lesions, the ossicular erosion involving the ossicular chain detachment increased its influence on performance of round-window stimulation at the low frequency. Therefore, the effect of otitis media on the hearing compensation performance of round-window stimulation should be considered comprehensively when designing its actuator, especially the low-frequency deterioration caused by the thickening and the hardening of the tympanic membrane; the actuator's low-frequency output should be enhanced accordingly to ensure its postoperative hearing compensation performance.

Surgeon oriented preoperative radiologic evaluation in cochlear implantation - our experience with a proposed checklist

Introduction: Preoperative temporal bone imaging studies have been routinely performed prior to cochlear implantation. Radiologists need to report these examinations with special focus on the surgeon's expectations. Objectives: To provide a basic structured format, in the form of a checklist, for reporting preoperative computed tomography (CT) and to its clinical impact on operative findings. Methods: The preoperative temporal bone CT scans of 47 patients were analyzed and reported according to the proposed checklist. Intraoperative assessment of mastoidectomy, posterior tympanotomy and round window access was done by the surgeon in a blinded fashion and were correlated with the radiological findings to assess its significance. Results: The proposed radiological checklist was reliable in assessing operative difficulty during cochlear implantation. Contracted mastoid and lower tegmen position were associated with a greater difficulty of the cortical mastoidectomy. Presence of an air cell around the facial nerve (FN) was predictive of easier facial recess access exposure. Facial nerve location and posterior external auditory canal (EAC) wall inclination were predictive of difficult round window (RW) accessibility. Conclusion: Certain parameters on the preoperative temporal bone CT scan may be useful in predicting potential difficulties encountered during the key steps involved in cochlear implant surgery (AU)

Feedback of Dynamic Responses from the Middle Ear for Round Window Closure with Different Pathology / 医用生物力学

Objective To analyze the influence of round window lesion on dynamic responses from the middle ear. Methods Based on CT scan images of healthy human ear, the three-dimensional finite element model of human ear was rebuilt by PATRAN software, then NASTRAN software was applied to conduct coupled solid-fluid frequency response analysis. The feedback of round window lesion on dynamic response of the middle ear was investigated by numerical simulation. Results Round window closure caused by sclerosis led to more decline in amplitude of stapes than congenital round window closed, maximally can reach 30.2 dB, and the latter had no obvious influence on velocity of stapes. In term of phase angle, on condition of sclerosis, change of phase for stapes and round window reached 90° at most and kept a difference value of 180°. In contrast, on condition of congenital round window closed, change of phase for stapes reached 270° at most，meanwhile change of phase for round window disappeared. Conclusions The dynamic response of the middle ear showed different feedback to congenital and otosclerotic round window fixation based on amplitude, velocity and phase. The research findings provide the theoretical basis for diagnosing and fixing round window lesion in future.

The effect of preload and support's stiffness on the performance of round window stimulation: a numerical analysis / 生物医学工程学杂志

To investigate the influence of the preload and supporting stiffness on the hearing compensation performance of round window stimulation, a coupling finite model composed of a human ear, an actuator and a support was established. This model was constructed based on a complete set of micro-computed tomography (Micro-CT) images of a healthy adult's right ear by reverse engineering technology. The validity of the model was verified by comparing the model's calculated results with experimental data. Based on this model, we applied different amplitude preloads on the actuator, and changed the support's stiffness. Then, the influences of the actuator's preload and the support's stiffness were analyzed by comparing the corresponding displacements of the basilar membrane. The results show that after applying a preload on the actuator, its hearing compensation performance was increased at the middle and high frequencies, but was deteriorated at low frequencies; besides, compared with using the fascia as the actuator's support in clinical practice, utilizing the titanium alloy to fabricate the support would enhance the hearing compensation performance of the round window stimulation in the whole frequency range.

Numerical analysis on sound compensation performance of round window stimulation in typical middle ear diseases / 医用生物力学

Objective To study the effect of typical middle ear diseases on sound compensation of round window (RW) stimulation, so as to provide references for the optimal design of middle ear implants by RW stimulation. Methods The finite element model of the middle ear and cochlea was built by CT scanning and reverse engineering technique, and its reliability was also verified. On the basis of the model and by changing material properties of corresponding tissues, three typical middle ear diseases were simulated: hardening of stapedial annular ligaments, abnormal stapedial bone growth and hardening of anterior mallear ligaments. Then the response from displacement of basilar membrane (BM) was compared to analyze the impact of 3 types of middle ear diseases on sound compensation of RW stimulation. Results The stapes with abnormal bone growth severely deteriorated the equivalent sound pressure (ESP) of RW stimulation at higher frequencies, while the hardening of stapedial annular ligaments and the hardening of anterior malleus ligaments prominently decreased ESP of RW stimulation at lower frequencies. Among the 3 types of middle ear diseases, hardening of stapedial annular ligaments affected the sound compensation of RW stimulation more significantly with the amount of the ESP reduction up to 17 dB. Conclusions Middle ear diseases can deteriorate the sound compensation of RW stimulation seriously with large deterioration, Therefore, the output stimulation of the actuator should be targeted to improve the design of the middle ear implants by RW stimulation.

Prediction of round window visibility in cochlear implantation with temporal bone high resolution computed tomography / 中华耳鼻咽喉头颈外科杂志

Objective@#To discuss the prediction of round window(RW) visibility in cochlear implantation(CI) with temporal bone high resolution computed tomography(HRCT).@*Methods@#From January 2013 to January 2017, 130 cases underwent both HRCT and CI in our hospital were analyzed. The distance from facial nerve to posterior canal wall(FWD), the angle between facial nerve and inner margin of round window(FRA), and the angle between facial nerve and tympanic anulus to inner margin of round window(FRAA) were detected at the level of round window on axial temporal bone HRCT. A line parallel to the posterior wall of ear canal was drawn from the anterior wall of facial nerve at the level of round window on axial temporal bone HRCT and its relationship with round window was detected (facial-round window line, FRL): type0-posterior to the round window, type1-between the round window, type2-anterior to the round window. Their(FWD, FRA, FRAA, FRL) relationships with intra-operative round window visibility were analyzed by SPSS 17.0 software.@*Results@#FWD(F=18.76, P=0.00), FRA(F=34.57, P=0.00), FRAA (F=14.24, P=0.00) could affect the intra-operative RW visibility significantly. RW could be exposed completely during CI when preoperative HRCT showing type0 FRL. RW might be partly exposed and not exposed when preoperative HRCT showing type1 and type2 FRL respectively.@*Conclusion@#FWD, FRA, FRAA and FRL of temporal bone HRCT can predict intra-operative round window visibility effectively in CI surgery.

Residual Hearing Preservation with the Evo® Cochlear Implant Electrode Array: Preliminary Results

Abstract Introduction The preservation of residual hearing is currently an important challenge for cochlear implant surgeries. Indeed, if patients exhibit functional hearing after cochlear implantation, they can benefit from the combination of acoustical stimulation, usually in the low-frequencies and electrical stimulation in the high-frequencies. This combined mode of stimulation has proven to be beneficial both in terms of speech perception and of sound quality. Finding the right procedures for conducting softsurgeries and designing electrode arrays dedicated to hearing preservation is an open issue. Objective The objective of this study is to evaluate the combination of a soft-surgery procedure implicating round-window insertion and the use of dexamethasone and hyaluronic acid during surgery, with the use of a specifically designed straight soft electrode array, on hearing preservation in patients with functional hearing in the low frequencies. Methods This pre-clinical trial was conducted on seven patients with residual hearing in the low frequencies. The surgical method used employed a round window insertion and the use of topical dexamethasone. Results The soft-surgery protocol could be successfully followed in five patients. In this group, the average hearing threshold shift compared with pre-operative values was of 18.7 þ/ 16.1 dB HL up to 500 Hz and 15.7 þ/ 15.1 up to 1 kHz, demonstrating satisfying levels of hearing preservation. Conclusion We were able to demonstrate the possibility of preserving residual hearing in most of the patients using the EVO electrode. Significant residual hearing preservation levels were was obtained when a soft surgical approach involving round window insertion, dexamethasone and hyaluronic use during the surgery.

Ruido eléctrico de la ventana redonda / Round window electrical noise

Desde hace décadas se sabe que al colocar un electrodo cerca de la ventana redonda de la cóclea es posible registrar potenciales cocleares en respuesta a estímulos sonoros, tales como el potencial microfónico coclear o el potencial de acción compuesto del nervio auditivo. Sin embargo, hace algunos años, se ha descrito que al posicionar un electrodo en el nicho de la ventana redonda en animales de experimentación y en ausencia de estimulación acústica, se obtiene actividad eléctrica aparentemente aleatoria y no desencadenada por estímulo. Esta actividad eléctrica se ha denominado ruido eléctrico de ventana redonda (RWN, por su sigla en inglés Round Window Noise) y representaría la descarga espontánea de fibras del nervio auditivo. La técnica para su registro es similar a la utilizada en la electrococleografía para obtener potenciales cocleares en humanos. Esta señal se distingue del ruido eléctrico no biológico por tener un peak en su poder espectral centrado en torno a los 900 Hz. La amplitud de esta banda de frecuencia se correlaciona con la sensibilidad auditiva en la región basal de la cóclea, entre los 12 a 30 kHz en cobayos y gatos. El RWN se ha estudiado a través de estimulación acústica y bloqueo farmacológico, logrando caracterizar sus propiedades electrofisiológicas para desarrollar modelos de estudio con aplicación clínica.

For decades, it has been known that placing an electrode near the round window niche allows the recording of cochlear potentials in response to auditory stimuli, such as the cochlear microphonic potential and the compound action potential of the auditory nerve. However, some years ago, it was discovered, that by positioning an electrode in the round window niche of experimental animals, and in the absence of acoustic stimulation, apparently random electrical activity is obtained. This electrical activity is called round window electrical noise (RWN) and represents the spontaneous discharge of auditory nerve fibers. The recording technique is similar to that used in electrocochleography in humans. This bioelectrical signal is distinguished from that of non-biological electrical noise, as it has a power spectral peak centered around 900 Hz. The magnitude of this frequency peak is correlated with hearing sensitivity in the basal region of the cochlea, between 12 to 30 kHz in guinea pigs and cats. The RWN has been characterized using sound stimulation or pharmacologic suppression, and its electrophysiological properties could be used to develop models of auditory nerve function with possible clinical application.

Sensorineural hearing loss in patients with unilateral safe chronic suppurative otitis media.

Background: Chronic Suppurative Otitis Media (CSOM) is the major cause of hearing impairment, mainly conductive type of hearing loss. The occurrence of sensorineural hearing loss (SNHL) in CSOM is controversial and the controversy is more for safe mucosal type. This study aims to assess the association between SNHL and safe mucosal CSOM and its relation to patient’s age, sex, duration of disease, active or inactive disease and speech frequencies. Methods: 100 patients with unilateral mucosal type of CSOM with normal contralateral ear were included in the study. The infected ear was taken as study ear and normal ear as control ear in all patients. All patients underwent hearing assessment by pure tone audiometry for both ears. In case of active disease, ear discharge was first cleared and then audiometric assessment done. Results were statistically compared in all patients for both study and control ears using parameters of patient’s age, sex, duration of disease, speech frequency and active or inactive disease. Results: There was significant higher number of study ears with CSOM having average bone conduction threshold of all frequencies above 25 decibels which implies SNHL (21%) compared to control contralateral ears without infection (5%). There was higher incidence of SNHL at higher speech frequencies. The incidence also increased with age of patient and duration of disease. The incidence was higher in active stage than inactive or quiescent stage. There was no difference among males and females. Conclusion: Safe mucosal CSOM can cause significant SNHL and risk increases with increasing age, duration of disease, higher speech frequencies and presence of active disease.

Critical Evaluation of Round Window Membrane Sealing in the Treatment of Idiopathic Sudden Unilateral Hearing Loss

OBJECTIVES: Rupture of the round window membrane with consecutive development of a perilymphatic fistula (PLF) is still a matter of controversial debate in the pathogenesis of idiopathic sudden sensorineural hearing loss (SSHL). Until now no consensus exists about whether these patients benefit from performing an exploratory tympanotomy with sealing of the round window. The aim of the present study was to analyze critically the effectiveness of sealing the round window membrane in patients with SSHL. METHODS: The clinical data of 51 patients with SSHL and a mean hearing decline of at least 60 dB over 5 frequencies who were treated with tympanotomy and sealing of the round window membrane were retrospectively analyzed. The results have been compared to the current state of the literature. RESULTS: Intraoperatively a round window membrane rupture or fluid leak was observed in none of the patients. After performing tympanotomy the mean improvement of hearing level was 32.7 dB. Twenty of 51 examined patients (39.2%) showed a mean improvement of the hearing level of more than 30 dB and a complete remission could be detected in 12 patients (23.5%). Reviewing the literature revealed no standard guidelines for definition or treatment of SSHL as well as for evaluation of hearing loss and its recovery. CONCLUSION: The results of the present study and the literature should be discussed critically. It is unclear whether tympanotomy and sealing of the round window membrane may be a meaningful treatment for SSHL. Therefore this procedure should be discussed as a therapeutic option only in selected patients with sudden deafness or profound hearing loss in which PLF is strongly suspicious or conservative treatment failed.

The Treatment of Traumatic Superior Semicircular Canal Fracture using Round and Oval Window Reinforcements / 听力学及言语疾病杂志

Objective To explore the surgical procedure and effects of the round and oval window reinforce‐ments in controlling the vestibular symptoms induced by traumatic superior semicircular canal (SSC) fracture .Meth‐ods The clinical course of a patient of traumatic SSC fracture treated with round and oval window reinforcements were reviewed .The essential points of diagnosis ,surgical method ,and efficacy were discussed .Results The patient experienced low frequency sound - induced vertigo ,feelings of body uprush ,blurred vision ,insupportableness of low - frequency vibration ,loss of proprioceptive sensation of the head ,hearing loss ,ear fullness ,and autophony af‐ter a car accident .A high - resolution temporal bone CT revealed multiple fractures in the left SSC and a single frac ‐ture in the right SSC .A diagnosis of the SSC fracture was made .An exploratory tympanotomy was performed using a transcanal tympanomeatal flap approach under local anesthesia .A piece of abdominal fat was used to fill the round window .A trimmed temporal fascia was placed over the fat on the round window and surrounding the edge of stape‐dial footplate .Fibrin glue was applied to secure the conjunction between temporal fascia and tympanic mucosa .Tita‐nium partial ossicular replacement prosthesis was used to reconstruct the ossicular chain .Immediately after the oper‐ation ,the symptoms of sound - induced vertigo ,the feeling of body uprush ,agitation ,blurred vision ,tinnitus ,ear fullness ,and autophony disappeared .The proprioceptive sensation became normal on the left side of the head and improved on the right side .Fourteen days post - operation ,audiogram demonstrated that the bone conduction at 4 kHz recovered for more than 20 dB and the air - bone gap increased throughout all the frequencies of in the left ear .Conclusion The minimally invasive round and oval window reinforcement is an effective treatment for traumatic SSC dehiscence syndrome .

Isosorbide Concentration in Perilymph of the Guinea Pig After Oral Administration Versus That After Round Window Perfusion

OBJECTIVES: The aims of this study were to investigate the feasibility of isosorbide delivery into perilymph through the round window membrane (RWM), and to compare the intracochlear isosorbide concentration in perilymph after oral administration (PO) versus that after round window perfusion (RWP). METHODS: Sixteen male guinea pigs (32 ears) were used. Isosorbide, an osmotic diuretic, was administered via RWP or PO. First, to investigate the optimal perfusion time, perilymph sampling of scala tympani from the RWM was performed after RWP for 15, 30, or 60 minutes. Second, to compare the drug concentration after RWP versus that after PO, perilymph was aspirated at 3 and 6 hours after administration. Intracochlear concentration of isosorbide was analyzed by high-performance liquid chromatography coupled to refractive index detection. RESULTS: Isosorbide passed through the RWM into perilymph after RWP. After RWP for 15, 30, and 60 minutes, mean isosorbide concentrations in perilymph were 116.27+/-44.65, 245.48+/-112.84, and 279.78+/-186.32 mM, respectively. The intracochlear concentration after RWP for 30 minutes was higher than that after RWP for 15 minutes (P=0.043). At 3 and 6 hours after PO, isosorbide concentrations in perilymph were 28.88+/-4.69 and 12.67+/-2.28 mM, respectively. In contrast, the corresponding concentrations after RWP were 117.91+/-17.70 and 75.03+/-14.82 mM at 3 and 6 hours, respectively. Isosorbide concentrations in perilymph following RWP were significantly higher than those following PO at both 3 and 6 hours (P=0.025 and P=0.034, respectively). CONCLUSION: Isosorbide can rapidly pass through the RWM after RWP in guinea pigs, and 30 minutes of perfusion is considered to be appropriate. In addition, over a 6-hour period, RWP can deliver higher concentrations of isosorbide into perilymph than those achieved with PO.

Blocking NR2B Receptor Reversed the Process of Cytotoxicity to Spiral Ganglion Neurons Induced by Sodium Salicylate in Guinea Pig / 听力学及言语疾病杂志

Objective To investigate whether blocking NR2B receptor can reverse the process of cytotoxicity to spiral ganglion neurons induced by sodium salicylate in guinea pig by applying ifenprodil (a NR2B antagonist) at the round window niche .Methods Sixty healthy guinea pigs provided by the experimental animal center of Guangxi medical university were randomly and evenly divided into a control group (Group I ,no treatment) ,an APL group (Group II ,60μl APL directly applied to the round window ) ,a sodium salicylate group (Group III ,60 μl APL di-rectly applied to the round window and then be given intraperitoneal sodium salicylate injection ) ,and an ifenprodil group (Group IV ,60μl of 10μmol/l ifenprodil in APL directly applied to the round window and then be given intra-peritoneal sodium salicylate injection ) .Sodium salicylate was given at 400 mg · kg -1 · d-1 for 7 days .Auditory brainstem responses (ABRs) were recorded before animal sacrifice by decapitation .The left cochlea was removed and prepared for detection of caspase -3 expression in spiral ganglion neurons via immunohistochemistry .From each group ,6 cochleae were used to test apoptosis index in spiral ganglion neurons using the TUNEL technique .Results Before salicylate administration ,the ABR threshold was less than 40 dB SPL in all animals .After salicylate ad-ministration ,the ABR threshold was 33 .33 ± 5 .17 dB SPL in Group II ,64 .17 ± 7 .36 dB SPL in Group III and 49 .17 ± 5 .85 dB SPL in Group IV ,in contrast to 31 .67 ± 5 .16 dB SPL in Group I (controls) .The caspase -3 ex-pression was not changed obviously in Group I and Group II ,but was significantly changed in Group III and Group IV (P<0 .01) .The caspase-3 expression appeared to be decreased in Group IV compared to those in Groups III (P<0 .05) ,but still increased compared to those of in Group I and II (P<0 .05) .The apoptosis index among spiral ganglion neurons in Groups III and IV increased significantly compared to those of in Group I and II (P<0 .001) .It was however ,lower in Group IV than in Group III (P<0 .01) .Conclusion Blocking NR2B receptor with specificity can reverse the process of cytotoxicity to spiral ganglion neurons induced by sodium salicylate in guinea pig .

Cochlear Implantation with Round Window Insertion in Patients with Otitis Media with Effusion / 听力学及言语疾病杂志

Objective To study the indications ,surgical techniques of cochlear implantation in bilateral severe sensorineural hearing loss patients with otitis media with effusion .Methods Retrospective study of the data was col-lected from 30 bilateeral severe sensorineural hearing loss patients receiving cochlear implantation .CI was performed with round window insertion in 30 patients with otitis media with effusion .Results One stage operations of CI with round window insertion were carried out for 30 patients with otitis media with effusion .All electrodes were implan-ted successfully ,in which the CI went normally and electrode array were protected well .All implant devices had worked normally and all patients had performed well during an average of 1~3 years follow -up .Conclusion Bilat-eral severe sensorineural hearing loss patients with otitis media with effusion could be performed cochlear implanta-tion with round window insertion in one stage ,and it was safe and effective .

Protection Against Gentamicin Ototoxicity by the Administration of Dexamethasone on the Cochlear Round Window Membrane / 听力学及言语疾病杂志

Objective To investigate the protective effects of round window membrane administration of dex-amethasone(Dex) on ototoxicity induced by gentamicin(GM) .Methods Sixty guinea pigs with normal hearing were randomly divided into four groups ,①GM group :treated with gentamicin by 120 mg · kg -1 · d-1 for 10 days;②GM -S-Dex group:treated as the GM group and dexamethasone by intraperitoneal injection 2 .5 mg · kg -1 · d-1 for 10 days;③GM -T -Dex group :treated as the GM group and dexamethasone by round window administration on right ear ;④NS -T -Dex group:treated with sodium chloride by 120 mg · kg -1 · d-1 for 10 days and with dex-amethasone topically as GM -T -Dex group .The auditory brainstem response (ABR) was respectively measured before the treatment and on day 1 ,day 10 after the treatment .After the treatment ,animals were killed instantly and the middle ear mucosa and the Corti's organ were observed with SEM .Results There was no change of ABR threshold in NS -T -Dex group on day 10 after the treatment ,whereas ABR thresholds in the other groups were elevated and GM group was the most significant .The massive outer hair cells loss was observed in GM group while the loss in GM -T -Dex group and GM -S-Dex group was trivial .The middle ear mucosa was normal and no inflammation was found in any of the groups .Conclusion The results indicated that round window administration of dexamethasone had protective effects aganist the gentamicin -induced hearing loss .