Round Window Approach Research Articles

Crista Fenestra Heights Measured by HRCT Predicts the Necessity for Extended Round Window Approach for Slim Modiolar Electrode.

To evaluate the morphology of the crista fenestra (CF) using three-dimensional reconstruction based on high-resolution computed tomography (HRCT) and to examine the influence of CF height on the insertion approach used for CI632/532 implants. Retrospective study. Tertiary referral center. Forty-five ears of 37 patients who received CI632/532 implants were included. HRCT images were reconstructed into three-dimensional images, and CF structures were identified. The patients were divided into two group based on the insertion approach: round window approach (RW; n = 27) and extended round window approach (eRW; n = 18). To evaluate CF interference, 10 cases in the eRW group in which the sheath or electrode did not pass through the RW before widening the RW niche (nRW group) were specifically included in the analysis. The identified CF cross-sections were confirmed by HRCT axial sectioning, and CF heights were measured. The mean CF height was significantly greater in the nRW group than in the RW group (0.97 vs. 0.78 mm). CF was identified using three-dimensional computer graphics (3DCG) and the CF height on the HRCT axial sections. Thus, measuring the CF height using 3DCG reconstruction can facilitate the preoperative selection of the electrode insertion approach.

Cochlear Implantation in a Patient with Intractable Tinnitus: A Case Report of an Endoscope-Assisted Approach.

Preservation of residual hearing and vestibular function is a crucial factor in cochlear implantation (CI), especially in patients with residual low-frequency hearing thresholds. We report a case of a patient who underwent unilateral endoscope-assisted CI with a challenging surgical view following rigorous posterior tympanotomy. A 53-year-old male presented with left-sided intractable tinnitus due to sudden sensorineural hearing loss that had occurred 10 years prior. Due to the abnormal location of the round window (RW), which was far more posterior and inferior than usual and impeded insertion of the electrode using the conventional RW approach, endoscope-assisted CI was performed. Pure-tone audiometry at 3 months after CI revealed satisfactory hearing thresholds. Furthermore, there was alleviation of the left-sided tinnitus, which was indicated by a marked decrease in both the subjective visual analog scale loudness and Tinnitus Handicap Inventory scores. With proper indications, we strongly recommend applying the RW approach with endoscopic assistance over conventional bony cochleostomy for the preservation of low-frequency hearing thresholds in cases where RW visualization is insufficient following posterior tympanotomy.

Prediction of difficult round window visibility during cochlear implantation via a reformatted CT facial recess view: A retrospective study with surgical correlation.

Cochlear implant surgery is performed commonly through the facial recess via the round window (RW) approach. This study aims to evaluate the utility of reformatting the pre-operative CT temporal bone scan into a CT facial recess view in alerting surgeons to a potentially difficult surgery with poorly visualized round window. This is a retrospective study of 41 patients (43 ears), who had undergone cochlear implant surgery. Intraoperative findings of round window position relative to 2nd genu-mastoid portion of facial nerve, and round window membrane orientation were recorded by the surgeons. Pre-operative CTs were analyzed by two radiologists in axial and a reformatted facial recess plane that simulates the surgeon's view via the facial recess. Radiological assessment markers include the facial nerve-chorda tympani nerve width (FN-CTN) measured 1.2mm inferior to the exit point of the chorda tympani nerve into the tympanic cavity, round window position relative to 2nd genu-mastoid segment of the facial nerve and RW membrane's angle from the vertical axis. The best predictor for difficult round window intraoperative visibility is the RW position relative to the 2nd genu-mastoid segment of the facial nerve lying lateral to it on CT facial recess reformatted images. A RW that lies partially to completely posterior to the posterior border of the 2nd genu-mastoid segment of the facial nerve had up to 55.6% risk of encountering difficult access, while those positioned anterior to or partially anterior to the anterior edge of the 2nd genu-mastoid segment of the facial nerve had 0% risk of difficult access (p<0.05). There are substantial agreements in the intra-rater (Kappa=0.751, p<0.001) and inter-rater reliability (Kappa= 0.698, p<0.001). There is no significant association between surgical difficulty and facial nerve-chorda tympani distance or RW angle (p>0.05). Identification of round window positions in the reformatted CT facial recess view is a useful tool in predicting potentially difficult round window access in cochlear implant surgery. RW= Round window, FN-CTN= facial nerve to chorda tympani nerve width.

Noise exposure of the inner ear during robotic drilling.

Preserving the cochlear structures and thus hearing preservation, has become a prominent topic of discussion in cochlear implant (CI) surgery. Various approaches and soft surgical techniques have been described when approaching the inner ear. Robot-assisted cochlear implant surgery (RACIS) reaches the round window in a minimally invasive manner by following a trajectory of minimal trauma. This involves the drilling of a keyhole trajectory to the round window, through the facial recess, with no need for a complete mastoidectomy. It involves less drilling, less drilling time and less structural damage. A lot of attention has been paid to the structural traumatic causes of hearing loss but acoustic trauma during the exposure of the inner ear appears to be neglected topic. The aim was to measure the noise exposure of the inner ear during the robotic drilling of the mastoid and bony overhang of the round window. The results were compared with the milling in conventional cochlear implantation surgery. RACIS on fresh frozen human cadavers. The equivalent frequency-weighted and time-averaged sound pressure level LAF in dB and the noise dose in % derived from a noise damage model, both obtained during RACIS. The robotic drilling of 6 trajectories towards the inner ear were performed, including 4 trajectories through round window access and 2 trajectories through cochleostomy. The results were compared with the data of 7 cases of conventional CI surgery that have been described in literature. The induced equivalent sound pressure level LAF was determined via an accelleration sensor at the zygomatic arch and a calibration according to bone conduction audiometry. A noise dose for the whole procedure was calculated from the equivalent sound pressure level LAF and the exposure time using a noise damage model. A noise dose of 100% is considered a critical exposure limit and values above are considered potentially harmful, with the risk of hearing impairment. The maximum LAF was 82 dB during fiducial screw placement; 87 dB during middle ear access; 95 dB for the accesses through the round window and 88 dB for the accesses through cochleostomy. The noise dose due to the HEARO®-procedure was always far below the critical value of 100%. There was no acoustic trauma of the inner ear in all cases with the noise dose being smaller than 0.1% in five out of the six cases. The maximum LAF in the seven cases of conventional CI surgery was 118 dB with a maximum cumulative noise dose of 172.6%. The critical exposure limit of 100% was exceeded in three cases of conventional CI surgery. RACIS provokes significantly less acoustic trauma than conventional mastoid surgery in our findings. There were no observable differences in noise exposure levels between a cochleostomy or a round window approach where the bony overhang needed to be drilled.

Impedance and Functional Outcomes in Robotic-Assisted or Manual Cochlear Implantation: A Comparative Study

Introduction: Preservation of residual hearing, mainly the low frequencies, is the current main objective of cochlear implantation. New electrode arrays and the development of minimally invasive surgery have allowed electroacoustic stimulation. Over the past several years, robotic-assisted cochlear implant surgery aimed to improve the insertion process while respecting inner ear structures. However, the introduction of a foreign body inside the cochlea can lead to the development of fibrous tissue around the electrode array, or even induce osteogenesis. These histological changes disrupt the parameters of the cochlear implant, resulting in elevated impedance. In addition, long-term auditory performance can be affected, with a deterioration in word comprehension. We evaluated the potential impact of RobOtol® on impedance changes over time, leading to potentially positive functional outcomes. Methods: Cochlear implant surgery with a round window approach was performed under general anesthesia. Fifteen Med-El Flex24 electrode arrays were inserted manually and 24 using RobOtol®. All subjects underwent pure-tone audiometry tests before the surgery and at regular intervals up to 1 year after the surgery. Based on the pure-tone average at the low frequencies from 250 to 1,000 Hz, we divided the patients according to the degree of auditory preservation (full preservation ≤15 dB, partial preservation 15 dB–30 dB, significant loss >30 dB). These different groups were compared in terms of impedance changes and auditory performance, specifically word recognition score. Results: We found proportionally fewer patients who experienced significant low-frequency hearing loss after robotic insertion (53.33% in the manual group compared to 41.67% in the robot-assisted insertion group). Impedance changes at the apex of the electrode array, especially at the first electrode (p = 0.04), after robotic surgery, with less overall variability, a continuous decreasing trend without secondary elevation, and lower values in cases of complete residual hearing preservation (for the three first electrodes: p = 0.017, p = 0.04, p = 0.045). The speech intelligibility amelioration over time showed favorable evolution in patients with complete residual hearing preservation regardless of the insertion method. However, in the absence of auditory preservation, the positive evolution continued more than 6 months after robotic surgery but stagnated after manual insertion (difference at 1 year, p = 0.038; median auditory capacity index 83% vs. 57%). Conclusion: Atraumatic electrode array insertion with consistent, slow speed and the assistance of RobOtol® minimizes disturbances in the delicate neurosensory structures of the inner ear and leads to better auditory performance.

Objective evaluation, using computed tomography, of round window access for cochlear implantation.

The aim of this study was to determine optimal radiological parameters for assessment of the round window approach in cochlear implantation surgery. Patients undergoing cochlear implantation at the Department of Otolaryngology in Szczecin, between 2015 and 2022 inclusive, were eligible for the study. Radiological assessments were performed according to eight parameters (seven proposed in the literature) and visibility clinical assessments were made intra-operatively on a scale of 1 to 5 (1 - not visible, 5 - fully visible). Visibility assessments of the round window niche (RWN) and round window membrane (RWM) allowed the difference (RWN minus RWM) to be used as a clinical assessment of the size of the overhang over the round window. Computed tomography images of 57 ears from 52 patients were analyzed in terms of round window access. The study group included 26 females and 26 males, ranging in age from 1 year to 80 years, with a median age of 41 years. In clinical assessment, round window visibility was rated as 5, after removal of the bone overhang, in 69% of patients. Cochlear access through the round window was achieved in 39 (68%) cases, extended access through the round window in 13 (23%) cases and cochleostomy was performed in 5 (9%) cases. Statistically significant ordinal correlations with round-window access were found using one parameter from the literature (Chen_Angle) and from our proposal (RWM_prediction). From parameters describing the bone overhang of the round window, positive correlations (using Kendall rank tests) were found using parameters from the literature (Sarafraz_OH and Mehanna_OH). Radiological measurements describing access to the round window which determine the angle based on the anatomy of the posterior wall of the auditory canal and the position of the facial nerve were found to be of the highest value. In the future, the use of algorithms for computed tomography evaluation and robot-assisted surgery will require parameters for assessing round window access, for surgery planning and choice of electrode. The parameters proposed by various authors are summarized, allowing researchers to assess their usefulness in further clinical practice.

Exploration of different electrode types inserted in a 3D model of a patient with incomplete partition type III inner ear malformation

BackgroundIncomplete partition type III (IP III) represents a rare malformation of the inner ear, posing challenges during cochlear implantation due to inevitable cerebrospinal fluid (CSF) leaks and the potential misplacement of electrodes within the internal auditory canal (IAC). Despite the absence of a consensus on electrode selection, literature suggests both straight and perimodiolar electrodes as viable options for proper insertion. Limited implantation series contribute to the ambiguity in electrode choice. In this study, we evaluated the insertion performance of three electrode types in a 3D model simulating an IP III patient's inner ear. MethodsA 3D model replicating the inner ear of a patient with IP III undergoing surgery was created, incorporating a canal wall up mastoidectomy and an enlarged round window approach. Insertions were carried out using a straight electrode, a perimodiolar electrode, and a slim perimodiolar electrode, inserted through a sheath in the basal turn of the cochlea. Electrode positions were assessed after each insertion, with each type being tested 20 times. ResultsSuccessful insertion rates were 95 % for the slim perimodiolar electrode, 85 % for the perimodiolar electrode, and 75 % for the slim straight electrode. Notably, the slim perimodiolar electrode required an adapted insertion technique due to the altered cochlear position in IP III cases. Statistical analysis revealed the slim perimodiolar electrode's superiority over the slim straight electrode in achieving successful insertions. ConclusionsThe 3D model of the IP III inner ear proved to be an effective tool for electrode testing and insertion training prior to surgery. Following multiple insertions in the 3D model, the slim perimodiolar electrode demonstrated the highest success rate, emphasizing its potential as the preferred choice for cochlear implantation in IP III cases.

Dependability of Electrode to Modiolus Distance in Patients Specific Electrode Selection: A Cadaveric Model Study.

This study aims to discern the disparities in the electrode-to-modiolus distance (EMD) between cochleostomy and round window approaches when performed sequentially in the same temporal bone. Additionally, the study seeks to identify the cochlear metrics that contribute to these differences. A cross-sectional study was conducted, involving the sequential insertion of a 12-electrode array through both round window and cochleostomy approaches in cadaveric temporal bones. Postimplantation high-resolution CT scans were employed to calculate various parameters. A total of 12 temporal bones were included in the imaging analysis, revealing a mean cochlear duct length of 32.892 mm. The EMD demonstrated a gradual increase from electrode 1 (C1) in the apex (1.9 ± 0.07 mm; n = 24) to electrode 12 (C12) in the basal turn (4.6 ± 0.24 mm; n = 12; p < 0.01). Significantly higher EMD values were observed in the cochleostomy group. Correlation analysis indicated a strong positive correlation between EMD and cochlear perimeter (CP) (rs = 0.64; n = 12; p = 0.03) and a strong negative correlation with the depth of insertion (DOI) in both the middle and basal turns (rs = - 0.78; n = 20; p < 0.01). Additionally, EMD showed a strong negative correlation with the DOI-CP ratio (rs = -0.81; n = 12; p < 0.01). The cochleostomy group exhibited a significantly higher EMD compared with the round window group. The strong negative correlation between EMD and DOI-CP ratio suggests that in larger cochleae with shallower insertions, EMD is greater than in smaller cochleae with deeper insertions. NA Laryngoscope, 134:4736-4744, 2024.

First Clinical Experience with a New Device for the Removal of Cochlear Schwannomas.

Background: In most cases, intralabyrinthine schwannoma (ILS) occurs in patients with unilateral hearing deterioration or neurofibromatosis type II (NF II). The pattern of localization of these tumors varies but mostly affects the cochlea. Extirpation of the cochlear schwannoma, if hidden by the cochlea modiolus, is difficult under the aspect of complete removal. Therefore, a tissue removal device (TRD) was designed and tested in temporal bones. The principle of handling the new device is a pushing and pipe cleaner handling inside the cochlea. This present study aimed to describe the first in vivo experience with the newly developed TRD for removing cochlear intralabyrinthine schwannomas. Methods: In three patients, the TRD was used for the tumor removal of cochlear schwannomas. In two patients with a cochlear schwannoma in combination with a cochlea implantation and one patient suffering from NF II, a cochlear schwannoma was removed with the TRD. The access was performed with a posterior tympanotomy, an enlarged round window approach and an additional second turn access. The device was inserted and extracted gradually from the second turn access until the rings were visible in the second turn access. By pushing and pipe cleaner handling, the tumors were removed. An MRI control was performed on the day postoperatively with a T1 GAD sequence. Results: Tumor removal with the TRD was performed in a 15-min procedure without any complications. An MRI control confirmed complete removal on the postoperative day in all cases. Conclusions: In vivo handling of the device confirmed straightforward handling for the tumor removal. MRI scanning showed complete removal of the tumor by the TRD.

Comparison of depth of electrode insertion between cochleostomy and round window approach: a cadaveric study.

Round window approach and cochleostomy approach can have different depth of electrode insertion during cochlear implantation which itself can alter the audiological outcomes in cochlear implant. The current study was conducted to determine the difference in the depth of electrode insertion via cochleostomy and round widow approach when done serially in same temporal bone. This is a cross-sectional study conducted in the Department of Otorhinolaryngology in conjunction with Department of Anatomy and Department of Diagnostic and Interventional Radiology over a period of 1year. 12-electrode array insertion was performed via either approach (cochleostomy or round window) in the cadaveric temporal bone. HRCT temporal bone scan of the implanted temporal bone was done and depth of insertion and various cochlear parameters were calculated. A total of 12 temporal bones were included for imaging analysis. The mean cochlear duct length was 32.892mm; the alpha and beta angles were 58.175° and 8.350°, respectively. The mean angular depth of electrode insertion via round window was found to be 325.2° (SD = 150.5842) and via cochleostomy 327.350 (SD = 112.79) degree and the mean linear depth of electrode insertion via round window was found to be 18.80 (SD = 4.4962) mm via cochleostomy 19.650 (SD = 3.8087) mm, which was calculated using OTOPLAN 1.5.0 software. There was a statically significant difference in linear depth of insertion between round window and cochleostomy. Although the angular depth of insertion was higher in CS group, there was no statistically significant difference with round window type of insertion. The depth of electrode insertion is one of the parameters that influences the hearing outcome. Linear depth of electrode insertion was found to be more in case of cochleostomy compared to round window approach (p = 0.075) and difference in case of angular depth of electrode insertion existed but not significant (p = 0.529).

Correlation of Scalar Cochlear Volume and Hearing Preservation in Cochlear Implant Recipients with Residual Hearing.

Preservation of residual hearing is one of the main goals in cochlear implantation. There are many factors that can influence hearing preservation after cochlear implantation. The purpose of the present study was to develop an algorithm for validated preoperative cochlear volume analysis and to elucidate the role of cochlear volume in preservation of residual hearing preservation after atraumatic cochlear implantation. Retrospective analysis. Tertiary referral center. A total of 166 cochlear implant recipients were analyzed. All patients were implanted with either a MED-EL (Innsbruck, Austria) FLEXSOFT (n = 3), FLEX28 (n = 72), FLEX26 (n = 1), FLEX24 (n = 41), FLEX20 (n = 38), or FLEX16 (n = 11, custom made device) electrode array through a round window approach. Main outcome measures: Cochlear volume as assessed after manual segmentation of cochlear cross-sections in cone beam computed tomography, and preservation of residual hearing 6 months after implantation were analyzed. The association between residual hearing preservation and cochlear volume was then assessed statistically. Rapid and valid cochlear volume analysis was possible using the individual cross-sections and a newly developed and validated algorithm. Cochlear volume had the tendency to be larger in patients with hearing preservation than in those with hearing loss. Significant correlations with hearing preservation could be observed for the basal width and length of the basal turn. Preservation of residual hearing after cochlear implantation may depend on cochlear volume but appears to be influenced more strongly by other cochlear dimensions.

Temporal bone histopathology in revision cochlear implantation

An increasing number of young infants, as early as six months of age with congenital hearing loss receive cochlear implantation, and it is probable that many of these patients will require revision surgery later in life. The possibility of explantation of the cochlear electrode and reimplantation may cause damage to the cochlea, compromising the speech perception outcome in revision implant is of concern. There is only one prior temporal bone histopathology study to look at the outcome of revision surgery and no prior study evaluating revision cochlear implantation that used the round window approach. We conducted a histopathological study of four temporal bone specimens from four patients who underwent revision cochlear implantation and when available post-operative speech perception tests were evaluated. In all cases, the reimplanted electrode followed into the same fibrous sheath without evidence of additional intracochlear damage due to revision surgery. The intracochlear damage from the initial cochlear implantation appears to be a more important factor in outcomes rather than changes associated with explantation and reimplantation.

Round Window Visibility in Cochlear Implantation : Pre-operative Prediction Using Various Radiological Parameters.

The round window approach has become the most preferred route for electrode insertion in cochlear implant surgery; however, it is not possible at times due to difficult round window membrane (RWM) visibility. Our study aims to investigate the relationship between preoperative radiological parameters and the surgical visibility of the RWM in Cochlear implant patients. A prospective cross-sectional study of 31 patients, age < 6 years, with bilateral severe to profound sensorineural hearing loss was conducted at a tertiary care hospital. The preoperative HRCT temporal bone scan was studied, and the parameters evaluated were facial nerve location, facial recess width, and RWM visibility prediction. All patients were operated on via the posterior tympanotomy. The surgical RWM visibility was done after optimal drilling of the posterior tympanotomy recess. The relationship between the radiological parameters and surgical visibility of RWM was evaluated. The difference in the facial nerve location as per the type of RWM was found to be significant (p value < 0.05). However, the facial recess width was not significantly associated with RWM visibility. The radiological prediction of RWM visibility by tracing the prediction line over RWM was significantly associated with intraoperative RWM visibility. The goal to look for preoperative scans is to predict the ease or difficulty of RWM visibility during surgery. The difficult visualization of the RWM, can result in dire intraoperative consequences. A comprehensive understanding of preoperative radiological parameters, coupled with meticulous surgical planning, is crucial to address these challenges effectively by focusing on enhancing RWM visualization.

Vestibular Preservation in Pediatric Cochlear Implantation.

Evaluate the rate of preserved vestibular function in pediatric cochlear implant surgery. Retrospective case review. Pre- and post-operative vestibular tests were compared in children who underwent cochlear implantation at a tertiary level pediatric hospital over a 4-year period. Data from 59 implanted ears in 44 children was included. Median age was 2.8 years at initial testing (range 7 months - 21 years) with 1:1 male/female ratio. Implant surgeries were 26 unilateral, 13 bilateral simultaneous, and 5 bilateral sequential. The majority were implanted with slim, non-styletted electrodes (86.4%) via a round window approach (91.5%). Normal pre-operative results were preserved post-operatively on rotary chair testing in 75% (21/28) of patients, cervical vestibular evoked myogenic potential testing in (75%) 30/40 of ears tested, ocular vestibular evoked myogenic potential testing in 85.7% (6/7) of ears tested, video head impulse testing in 100% (9/9) of ears tested, and computerized dynamic posturography in 100% (5/5) of patients tested. Overall, 62.5% of patients had no new deficits on any vestibular test performed post-operatively. Preservation rates of vestibular function following cochlear implant surgery were higher in this cohort than what has been reported in many earlier studies. Contemporary, less traumatic electrodes and insertion techniques may be a significant factor. The risk of causing a new, severe bilateral vestibular loss with long-term functional impacts appears to be low. Further study is warranted on the impacts of different cochlear implant electrode designs and insertion approaches on post-operative vestibular preservation. 4, Case Series Laryngoscope, 134:1913-1918, 2024.

Human Histology after Structure Preservation Cochlear Implantation via Round Window Insertion.

Current surgical techniques aim to preserve intracochlear structures during cochlear implant (CI) insertion to maintain residual cochlear function. The optimal technique to minimize damage, however, is still under debate. The aim of this study is to histologically compare insertional trauma and intracochlear tissue formation in humans with a CI implanted via different insertion techniques. One recent temporal bone from a donor who underwent implantation of a full-length CI (576°) via round window (RW) insertion was compared with nine cases implanted via cochleostomy (CO) or extended round window (ERW) approach. Insertional trauma was assessed on H&E-stained histological sections. 3D reconstructions were generated and virtually re-sectioned to measure intracochlear volumes of fibrosis and neo-ossification. The RW insertion case showed electrode translocation via the spiral ligament. 2/9 CO/ERW cases showed no insertional trauma. The total volume of the cochlea occupied by fibro-osseous tissue was 10.8% in the RW case compared with a mean of 30.6% (range 8.7%-44.8%, N = 9) in the CO/ERW cases. The difference in tissue formation in the basal 5 mm of scala tympani, however, was even more pronounced when the RW case (12.3%) was compared with the cases with a CO/ERW approach (mean of 93.8%, range 81% to 100%, N = 9). Full-length CI insertions via the RW can be minimally traumatic at the cochlear base without inducing extensive fibro-osseous tissue formation locally. The current study further supports the hypothesis that drilling of the cochleostomy with damage to the endosteum incites a local tissue reaction. 4: Case-control study Laryngoscope, 134:945-953, 2024.

Prognostic factors in pediatric cochlear implant: an outcome-based study.

To determine the prognostic factors in the pediatric cochlear implant (CI) outcome. This prospective cohort study was conducted on 289 pediatric cases with prelingual hearing loss who received cochlear implantation. Several possible salient factors have been recorded. Auditory and speech evaluations were performed before CI, as well as 6 and 12months after surgery, using Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) tests. According to univariate analysis, age at the time of surgery was a statistically significant factor. Neurological problems in the child, history of newborn infectious diseases, history of hearing aid use, proper parental cooperation, and round window approach were all significantly related to better auditory or speech outcomes. On the other hand, good parental cooperation and age (for CAP) and good parental cooperation, age, history of infectious disease, and hearing aids use (for SIR) are the significant factors in the multivariate setting. As evidenced by the obtained results, age, background diseases, history of rehabilitation with hearing aids, and surgical details are essential factors to be taken into account in the case-selection process.

Surgical anatomy of posterior tympanotomy: influence of the retrotympanum on round window exposure.

To describe how the retrotympanic structures could influence the visibility of the round window niche and the round window membrane during cochlear implant surgery, and to investigate if a round window approach is possible even in cases with unfavourable anatomy. Video recordings from 37 patients who underwent cochlear implantation were reviewed. The visibility of the round window niche and round window membrane at different timepoints was assessed according to a modified version of the Saint Thomas Hospital classification. The structures that concealed the round window niche and round window membrane were evaluated. After posterior tympanotomy, 54 per cent of cases had limited exposure (classes IIa, IIb and III) of the round window niche. After remodelling the retrotympanum, round window niche visibility significantly increased, with 100 per cent class I and IIa cases. Following remodelling of the round window niche, visibility of more than 50 per cent of the round window membrane surface was achieved in 100 per cent of cases. Remodelling the retrotympanum and the round window niche significantly increased exposure of the round window niche and round window membrane respectively, allowing round window insertion in all cases.

Histopathological reaction in the vestibule after cochlear implantation in Macaca fascicularis.

Cochlear implantation surgery (CI) is considered a safe procedure and is the standard treatment for the auditory rehabilitation in patients with severe-to-profound sensorineural hearing loss. Although the development of minimally traumatic surgical concepts (MTSC) have enabled the preservation of residual hearing after the implantation, there is scarce literature regarding the vestibular affection following MTCS.The aim of the study is to analyze histopathologic changes in the vestibule after CI in an animal model (Macaca fascicularis). Cochlear implantation was performed successfully in 14 ears following MTCS. They were classified in two groups upon type of electrode array used. Group A (n = 6) with a FLEX 28 electrode array and Group B (n = 8) with HL14 array. A 6-month follow-up was carried out with periodic objective auditory testing. After their sacrifice, histological processing and subsequent analysis was carried out. Intracochlear findings, vestibular presence of fibrosis, obliteration or collapse is analyzed. Saccule and utricle dimensions and neuroepithelium width is measured.Cochlear implantation was performed successfully in all 14 ears through a round window approach. Mean angle of insertion was >270° for group A and 180–270° for group B. In group A auditory deterioration was observed in Mf 1A, Mf2A and Mf5A with histopathological signs of scala tympani ossification, saccule collapse (Mf1A and Mf2A) and cochlear aqueduct obliteration (Mf5A). Besides, signs of endolymphatic sinus dilatation was seen for Mf2B and Mf5A. Regarding group B, no auditory deterioration was observed. Histopathological signs of endolymphatic sinus dilatation were seen in Mf 2B and Mf 8B.In conclusion, the risk of histological damage of the vestibular organs following minimally traumatic surgical concepts and the soft surgery principles is very low. CI surgery is a safe procedure and it can be done preserving the vestibular structures.

A new device for the removal of cochlear schwannoma: A temporal bone study.

Intralabyrinthine schwannoma (ILS) is a rare, mostly unilateral disease that causes deafness. Different intralabyrinthine sites of ILS can occur and can be removed by different surgical approaches. Cochlear ILSs are frequently partially hidden by the modiolus and therefore difficult to extirpate. Surgical techniques can be traumatic, offer limited surgical control during removal, and are time-consuming. The aim of this present study was to demonstrate the performance and handling of a newly developed device for the removal of cochlear intralabyrinthine schwannoma in the temporal bone. In a temporal bone study with a prepared posterior tympanotomy, an enlarged round window approach, and additional second turn access, a stiffened device with silicone rings was inserted and extracted gradually from the second turn access until the rings were visible in the second turn access. Insertion and extraction of the second cochlear access were easily performed. Pulling and pushing the silicone rings through the modiolus and hidden parts of the basal turn was possible and worked like a pipe cleaner. This newly developed tissue removal device in combination with the proposed surgical handling offers a new and less traumatic way to remove cochlear ILS.

Common challenges in cochlear implant surgery performed under local anaesthesia and how to overcome them: the experience of UK surgeons.

Cochlear implantation performed under local anaesthesia is an increasingly accepted technique worldwide, though the literature to date includes only single-surgeon and single-centre experiences. This study explored the national experience of UK surgeons using this challenging surgical technique, with the goal of providing consensus recommendations. A qualitative analysis was conducted of semi-structured interviews with 10 UK-based cochlear implantation surgeons, focusing on common challenges, how to overcome them and candidate selection. Cochlear implantation under local anaesthesia can potentially be offered to all eligible adult patients with favourable anatomy. A posterior tympanotomy and round window approach is recommended. Common challenges and recommendations are explored thematically: managing patient, surgeon and staff expectations; optimising communication; patient comfort and position; minimising pain and vertigo; and safe use of sedation. This is the first study of national experience of cochlear implantation performed under local anaesthesia. Key themes, including refinements to surgical technique and optimising patient comfort and communication, have been explored in depth.