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

OBJECTIVE: 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. METHODOLOGY: 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. RESULTS: 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). CONCLUSION: 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. LEVEL OF EVIDENCE: N/A Laryngoscope, 2024.

Cochlear Implantation in a Case of Relapsing Polychondritis With Profound Hearing Loss and Labyrinthine Ossification.

Relapsing polychondritis is an autoimmune disorder causing inflammation of cartilaginous structures, sensory epithelium, and cardiovascular system. Hearing loss is a rare and dreadful complication of this pathology. We report a case of relapsing polychondritis in a 38-year-old female who developed gradually progressive bilateral profound hearing loss. She did not have any improvement with medical management. Cochlear implantation was performed to rehabilitate her hearing. As the scala tympani was obliterated, a scala vestibuli insertion was performed. A complete insertion was possible with a compressed electrode, and she had good evoked compound action potential scores. Her categories of auditory performance scores were 6 at the end of one year. Patients with relapsing polychondritis can progress to profound hearing loss in rare cases and should be carefully followed up to identify early labyrinthine ossification. A scala vestibuli insertion can be performed with good outcomes in cases with ossification involving scala tympani. The surgeon should be ready for a middle-turn cochleostomy or a drill-out procedure in patients with advanced ossification.

Influence of inner ear impedance on middle ear sound transfer functions.

Introduction: For experimental studies on sound transfer in the middle ear, it may be advantageous to perform the measurements without the inner ear. In this case, it is important to know the influence of inner ear impedance on the middle ear transfer function (METF). Previous studies provide contradictory results in this regard. With the current study, we investigate the influence of inner ear impedance in more detail and find possible reasons for deviations in the previous studies. Methods: 11 fresh frozen temporal bones were prepared in our study. The factors related to inner ear impedance, including round window membrane stiffness, cochleostomy, cochlea fluid and cochlea destruction were involved in the experimental design. After measuring in the intact specimen as a reference (step 1), the round window membrane was punctured (step 2), then completely removed (step 3). The cochleostomy was performed (step 4) before the cochlear fluid was carefully suctioned through scala tympani (step 5) and scala vestibuli (step 6). Finally, cochlea was destroyed by drilling (step 7). Translational and rotational movement of the stapes footplate were measured and calculated at each step. The results of the steps were compared to quantify the effect of inner ear impedance changing related to the process of cochlear drainage. Results: As the inner ear impedance decreases from step 1 to 7, the amplitudes of the METF curves at each frequency gradually increase in general. From step 6 on, the measured METF are significantly different with respect to the intact group at high frequencies above 3 kHz. The differences are frequency dependent. However, the significant decrement of rotational motion appears at the frequencies above 4.5 kHz from the step 5. Conclusion: This study confirms the influence of inner ear impedance on METF only at higher frequencies (≥3 kHz). The rotational motions are more sensitive to the drainage of fluid at the higher frequency. Study results that found no influence of cochlea impedance may be due to incomplete drainage of the cochlea.

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

INTRODUCTION: 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. OBJECTIVE: 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. METHODOLOGY: 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 1 year. 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. RESULT: A total of 12 temporal bones were included for imaging analysis. The mean cochlear duct length was 32.892 mm; 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. CONCLUSION: 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).

Intralabyrinthine schwannoma: Surgical management and cochlear lumen preservation.

The present video reports the surgical removal of an intralabyrinthine schwannoma. The video contains patient's medical history, preoperative radiological evaluations and detailed description of surgical steps of the procedure, consisting in labyrinthectomy, cochleostomy and insertion of a dummy electrode in the preserved cochlear lumen within the context of a subtotal petrosectomy.

Persistent Stapedial Artery, Oval Window Atresia and Congenital Stapes Agenesis-Case Report.

Background: The persistent stapedial artery (PSA) is a rare congenital vascular malformation involving the middle ear. It is usually associated with pulsatile tinnitus and/or conductive hearing loss and can account for multiple risks during middle ear surgery. Case Report: we present a case of a 9-year-old male child with conductive hearing loss and persistent stapedial artery in his right ear, who was admitted to our ENT Department for hearing loss. During surgery, we discovered PSA along with congenital stapes agenesis and oval window atresia, as well as an abnormal trajectory of the mastoid segment of the facial nerve. After ossicular reconstruction (transcanal total ossicular replacement prosthesis) with cochleostomy, no surgical complications were recorded and hearing improvement was monitored by pre- and postoperative audiometry. Conclusion: Stapedial artery is a rare anatomical middle ear abnormality that can prevent proper surgical hearing restoration and can be associated with other simultaneous temporal bone malformations.

Acute effects of cochleostomy and electrode-array insertion on compound action potentials in normal-hearing guinea pigs.

Introduction: Electrocochleography (ECochG) is increasingly used in cochlear implant (CI) surgery, in order to monitor the effect of insertion of the electrode array aiming to preserve residual hearing. However, obtained results are often difficult to interpret. Here we aim to relate changes in ECochG responses to acute trauma induced by different stages of cochlear implantation by performing ECochG at multiple time points during the procedure in normal-hearing guinea pigs. Materials and methods: Eleven normal-hearing guinea pigs received a gold-ball electrode that was fixed in the round-window niche. ECochG recordings were performed during the four steps of cochlear implantation using the gold-ball electrode: (1) Bullostomy to expose the round window, (2) hand-drilling of 0.5-0.6 mm cochleostomy in the basal turn near the round window, (3) insertion of a short flexible electrode array, and (4) withdrawal of electrode array. Acoustical stimuli were tones varying in frequency (0.25-16 kHz) and sound level. The ECochG signal was primarily analyzed in terms of threshold, amplitude, and latency of the compound action potential (CAP). Midmodiolar sections of the implanted cochleas were analyzed in terms of trauma to hair cells, modiolar wall, osseous spiral lamina (OSL) and lateral wall. Results: Animals were assigned to cochlear trauma categories: minimal (n = 3), moderate (n = 5), or severe (n = 3). After cochleostomy and array insertion, CAP threshold shifts increased with trauma severity. At each stage a threshold shift at high frequencies (4-16 kHz) was accompanied with a threshold shift at low frequencies (0.25-2 kHz) that was 10-20 dB smaller. Withdrawal of the array led to a further worsening of responses, which probably indicates that insertion and removal trauma affected the responses rather than the mere presence of the array. In two instances, CAP threshold shifts were considerably larger than threshold shifts of cochlear microphonics, which could be explained by neural damage due to OSL fracture. A change in amplitudes at high sound levels was strongly correlated with threshold shifts, which is relevant for clinical ECochG performed at one sound level. Conclusion: Basal trauma caused by cochleostomy and/or array insertion should be minimized in order to preserve the low-frequency residual hearing of CI recipients.

A Rare Case of Cochlear Implant Electrode Array Misplacement Into the Posterior Semicircular Canal.

Cochlear implant electrode array misplacement is a rare but serious complication that may result in failure of hearing rehabilitation, non-auditory percepts, vestibular disturbance, or damage to adjacent neurovascular structures. We present a case of an elderly patient who suffered electrode array misplacement into the posterior semicircular canal, resulting in vestibular symptoms and severe downstream sequelae. The risk of misplacement may be higher in patients with a history of chronic otitis media or prior otologic surgery, and with the use of pre-curved electrode arrays. Electrophysiological testing and intraoperative imaging may allow for early detection and intervention in these cases. Laryngoscope, 133:175-177, 2023.

Cochlear promontory anatomy relevant to development of subendosteal and transpromontory electrodes using 192-section ultra-high resolution temporal bone CT imaging.

Objective: To characterize normative adult ranges for cochlear promontory thickness relevant to the development of subendosteal and transpromontory electrodes to rehabilitate various neurotologic disorders. Patients: Adults (≥18 years). Intervention: In vivo radiologic assessment using a 192-slice CT scanner (Force-192; Siemens Healthcare) with ultrahigh-resolution scan mode combined and iterative reconstruction. Main Outcome Measure: Cochlear promontory thickness. Results: Among 48 included patients (96 ears), the mean (SD) age was 56 (18) years (range 25-94) and included 25 (52%) women. Of that 12 patients (25%) had osteopenia (n = 6) or osteoporosis (n = 6). The mean (SD) body mass index was 28 (5) kg/m2. The mean (SD) promontory thickness for the 96 temporal bones under study was 1.22 (0.24) mm (range 0.55-1.85). There was not a statistically significant association between age and promontory thickness (correlation coefficient .08; p = .44). Promontory thickness was significantly greater for men than women (mean 1.28 vs. 1.17 mm; p = .03) and increased with increasing body mass index (correlation coefficient .30; p = .004). Last, promontory thickness was significantly less for patients with osteopenia or osteoporosis compared with those without these conditions (mean 1.09 vs. 1.27 mm; p = .002). Conclusions: Cochlear promontory thickness can vary by almost 1.5 mm across patients and is significantly associated with patient sex, body mass index, and comorbid osteopenia/osteoporosis. Subendosteal and transpromontory electrode placement techniques must account for this degree of variability. Level of Evidence: IV.

OTOPLAN-Based Study of Intracochlear Electrode Position Through Cochleostomy and Round Window in Transcanal Veria Technique.

To study the postoperative visualisation of the electrode array insertion angle through transcanal Veria approach in both round window and cochleostomy techniques. Retrospective study. Tertiary care centre. 26 subjects aged 2-15 years implanted with a MED-EL STANDARD electrode array (31.5 mm) through Veria technique were selected. 16 had the electrode insertion through the round window, 10 through anteroinferior cochleostomy. DICOM files of postoperative computer tomography (CT) scans were collected and analysed using the OTOPLAN 3.0 software. Examined parameters were cochlear duct length, average angle of insertion depth. Pearson's Correlation Test was utilized for statistical analysis. Average cochlear duct length was 38.12 mm, ranging from 34.2 to 43 mm. Average angle of insertion depth was 666 degrees through round window insertion and 670 degrees through cochleostomy insertion. Pearson's correlation showed no significant difference in average angle of insertion depth between subjects with cochleostomy and round window insertion. Detailed study on the OTOPLAN software has established that there remains no difference between round window insertion or cochleostomy insertion when it comes to electrode array position and placement in the scala tympani. It is feasible to perform round window insertion and cochleostomy insertion through transcanal Veria approach as this technique provides good visualisation. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-022-03228-5.

Complications of Cochleostomy Versus Round Window Surgical Approaches: A Systematic Review and Meta-Analysis.

We conducted a systematic review and meta-analysis to compare round window (RW) and cochleostomy (C) surgical approaches for the placement of cochlear implants (CIs). After obtaining the Institutional Review Board (IRB) approval, 213 peer-reviewed articles published between January 1, 2000, and August 1, 2021, comparing RW and C approaches were identified via a search on Google Scholar, Cochrane, and PubMed. The inclusion criteria were articles having an English version and involving only human subjects (cadaveric or alive). Statistical analysis of compiled electrode-to-modiolus distances was performed with two-sample independent t-tests. Live patients were categorized as having complete hearing preservation (<10 dB threshold shift), partial hearing preservation (10-20 dB shift), or minimal hearing preservation (>20 dB shift). Chi-squared testing was used to compare the distribution of hearing preservation categories between surgical approaches. Due to the heterogeneous nature of the data, only summative information was provided on the effects of approaches on trauma, electrical impedance, speech perception, vestibular dysfunction, ease of scala tympani insertion, and scalar shift. A total of 3,797 CI patients were evaluated. The RW approach resulted in a smaller (0.15 mm smaller on average, p<0.05) electrode-to-modiolus distance when compared to the C approach. The RW approach (93.0%) led to statistically better hearing preservation than the C approach (84.3%) (p<0.05). The RW approach was also associated with better outcomes in terms of speech perception, ease of scala tympani insertion, and reduced scalar shift. No difference between approaches was found with regard to trauma, electrical impedance, and vestibular dysfunction. Based on our findings, the RW approach appears to have several benefits compared to the C approach.

Standard Programming of Retrograde Electrode Insertion via Middle-Turn Cochleostomy in Labyrinthitis Ossificans.

Successful cochlear implantation in the setting of labyrinthitis ossificans is challenging. Various surgical techniques are described to circumvent the region of ossification and retrograde insertion of the electrode array is one such option. While reverse programming is often recommended in the case of retrograde electrode insertion, we present our experience of retrograde electrode insertion for labyrinthitis ossificans, where standard programming was adopted due to patient preference and provided satisfactory outcomes.

Evaluating cochlear insertion trauma and hearing preservation after cochlear implantation (CIPRES): a study protocol for a randomized single-blind controlled trial.

BACKGROUND: In order to preserve residual hearing in patients with sensorineural hearing loss (SNHL) who receive a cochlear implant (CI), insertion trauma to the delicate structures of the cochlea needs to be minimized. The surgical approach comprises the conventional mastoidectomy-posterior tympanotomy (MPT) to arrive at the middle ear, followed by either a cochleostomy (CO) or the round window (RW) approach. Both techniques have their benefits and disadvantages. Another important aspect in structure preservation is the design of the electrode array. Two different designs are used: a "straight" lateral wall lying electrode array (LW) or a "pre-curved" perimodiolar lying electrode array (PM). Interestingly, until now, the best surgical approach and design of the implant is uncertain. Our hypothesis is that there is a difference in hearing preservation outcomes between the four possible treatment options. METHODS: We designed a monocenter, multi-arm, randomized controlled trial to compare insertion trauma between four groups of patients, with each group having a unique combination of an electrode array type (LW or PM) and surgical approach (RW or CO). In total, 48 patients will be randomized into one of these four intervention groups. Our primary objective is the comparison of postoperative hearing preservation between these four groups. Secondly, we aim to assess structure preservation (i.e., scalar translocation, with basilar membrane disruption or tip fold-over of array) for each group. Thirdly, we will compare objective outcomes of hearing and structure preservation by way of electrocochleography (ECochG). DISCUSSION: Cochlear implantation by way of a cochleostomy or round window approach, using different electrode array types, is the standard medical care for patients with severe to profound bilateral sensorineural hearing loss, as it is a relatively simple and low-risk procedure that greatly benefits patients. However, loss of residual hearing remains a problem. This trial is the first randomized controlled trial that evaluates the effect of cochlear insertion trauma of several CI treatment options on hearing preservation. TRIAL REGISTRATION: Netherlands Trial Register (NTR) NL8586 . Registered on 4 May 2020. Retrospectively registered; 3/48 participants were included before registration.

[The significance of microanatomy of the round window in terms of cochlear implantation]. / Znachenie mikroanatomii okna ulitki dlya provedeniya kokhlearnoi implantatsii.

Sensoneural hearing loss is a polyetiological disease, which is often a secondary reflection of systemic pathology and is associated with damage of the cochlea and auditory nerve receptors. An important point in the surgical stage of cochlear implantation is the introduction of an implant active electrode into the cochleostomy spiral channel through the cochleostoma or round window. However, the issue of intra-cochlear structures surgical trauma in such surgical intervention seems to be very important, as it may reduce the success of subsequent rehabilitation. Therefore, the study of the anatomy of the round window and adjuscent areas was the objective of this work.

Round window anatomy predicts ease of cochlear implantation in children.

OBJECTIVES: We aim to evaluate the utility of the Round Window Angle (RWA) as a predictor of difficulty and operative time in cochlear implantation. METHODS: A retrospective study of pediatric patients that underwent cochlear implantation and CT temporal bone imaging from January 2008 to November 2019. Correlation, univariate, and multivariate analysis were conducted. RESULTS: 347 implantations met inclusion criteria. We found a difference in RWA for difficult (median: 101°, n = 5) and non-difficult (median: 74, n = 317) implantations (p < 0.0001). There was also a difference in RWA in patients with round windows visualized intra-operatively (p < 0.0197). When controlling for age and intraoperative round window visualization, logistic regression showed RWA was significantly associated with difficult insertion (OR: 1.687; p = 0.0246). Further, there was positive correlation between RWA and operative time (r = 0.1779, p = 0.0013) with patients with acute RWAs having shorter operative times (mean 115.7 ± 32.1 min) than those with obtuse RWA (mean 183.5 ± 97.0 min) (p = 0.0035). When accounting for surgeon and patient age, multivariate linear regression showed round window visualization (ß = 3.456, p = 0.0006) and obtuse RWA (ß = 6.172, p < 0.0001) was associated with an increase in operative time. CONCLUSION: Further research is needed to identify difficult cochlear implantations to increase the success and reduce risks associated with the surgery. Our study reports the possibility that an obtuse RWA both significantly increases difficulty and time of operation due to decreased round window visualization.

Spectral resolution and speech perception after cochlear implantation using the round window versus cochleostomy technique.

OBJECTIVE: To evaluate the spectral resolution achieved with a cochlear implant in users who were implanted using round window route electrode insertion versus a traditional cochleostomy technique. METHODS: Twenty-six patients were classified into two groups according to the surgical approach: one group (n = 13) underwent cochlear implantation via the round window technique and the other group (n = 13) underwent surgery via cochleostomy. RESULTS: A statistically significant difference was found in spectral ripple discrimination scores between the round window and cochleostomy groups. The round window group performed almost two times better than the cochleostomy group. Differences between Turkish matrix sentence test scores were not statistically significant. CONCLUSION: The spectral ripple discrimination scores of patients who had undergone round window cochlear implant electrode insertion were superior to those of patients whose cochlear implants were inserted using a classical cochleostomy technique.

Anatomy of the Round Window Region With Relation to Selection of Entry Site Into the Scala Tympani.

OBJECTIVES/HYPOTHESIS: The aim of cochlear implantation is to safely insert an electrode array into the scala tympani (ST) while avoiding damage to surrounding structures. There is disagreement on the optimal way of entering the ST-the round window (RW) approach versus cochleostomy. Regardless of the chosen approach, it is vital to understand the regional anatomy, which is complex, difficult to conceptualize, and rarely dissected in temporal bone courses. The goal of this study was to examine the anatomy of the RW to gain more in-depth knowledge on the local relationships of the anatomical structures and propose an approach for entering the ST in cochlear implant surgery tailored to the encountered anatomy. STUDY DESIGN: Cadaveric prevalence study and expert opinion with literature review. METHODS: Cadaveric temporal bone dissection (n = 13) by the first author assessing the RW anatomy. RESULTS: The round window membrane (RWM) and the osseous spiral lamina (OSL) are curved structures, each with a horizontal and a vertical part. The two horizontal portions are very closely apposed. The relationship between the OSL and the RWM determines the best site for a cochleostomy, which if required is best placed anteroinferiorly to the RWM. The distance between the oval window inferior margin and the RW membrane is less than 2 to 3 mm. The ST initially extends inferiorly and medially to the RW. CONCLUSIONS: The findings of our dissection have implications for cochlear implant surgery in aiming to avoid trauma to the OSL and basilar membrane and aid decision making in choosing the safest surgical approach. LEVEL OF EVIDENCE: 5. Laryngoscope, 131:E598-E604, 2021.

Round window accessibility during cochlear implantation.

OBJECTIVE: To assess data regarding round window (RW) visibility and surgical approaches in cochlear implant cases, and to describe and analyze surgical steps relevant for the RW approach in cochlear implantation. STUDY DESIGN: Prospective clinical study. METHODS: A questionnaire was completed by surgeons after each of altogether 110 cochlear implantations. Round window membrane (RWM) visibility was graded according to the St Thomas Hospital (STH) classification. RESULTS: Performing different surgical steps during the preparation of the RW niche, the RWM could be fully exposed (STH Type I) in 87%. A RW approach could be used for electrode insertion in 89% of the adult and 78% of the pediatric cases. The distribution of RW types differed significantly between adults and children. Drilling of the superior bony lip was the surgical step most frequently needed in adult as well as pediatric cases to obtain optimal RW exposure. CONCLUSION: In children, optimized surgical exposure of the RW niche resulted in only 52% full RWM visibility; whereas in adults, this could be achieved in 87%. The facial nerve (FN) had to be exposed at the level of the posterior tympanotomy in more than 70% of pediatric cases with full RWM visibility; while in adult cases with 100% visibility, such specific exposure was necessary in only 33%. Thus, surgical preparation of the RW niche seems to be more demanding in children than in adults.

Cochlear implantation outcomes with round window electrode insertion versus cochleostomy insertion.

OBJECTIVES: assessment of two techniques for electrode insertion during cochlear implantation which are the round window and the traditional cochleostomy insertions, the comparison utilized cochlear implantation outcomes. STUDY DEIGN: a prospective cohort study. PATIENTS: children (n = 200) between 2 and 8 years old who had bilateral severe to profound SNHL and received a unilateral cochlear implant, 100 children had a round window insertion and were labeled the RW group while the other 100 children had a cochleostomy insertion and were labeled the C group which was taken as a control group. OUTCOME MEASURE(S): all the participants in this study were followed up and tested twice for their cochlear implant outcomes, the first time when the duration of using their implants was no less than 24 months and no more than 30 months. The second time between 31 and 36 months post implantation. For speech perception; The Consonant-Nucleus-Consonant test (CNC) and The Bamford-Kowal-Bench sentence lists (BKB). For language acquisition; The Preschool Language Scale-fourth edition (PLS-4) and The Peabody Picture Vocabulary Test, Fourth edition (PPVT-4) had been utilized. For speech production; the Diagnostic Evaluation of Articulation and Phonology (DEAP). RESULTS: for speech perception: The mean CNC scores for the RW group and the C group between 24 and 30 months post-implantation and at 31-36 months post-implantation were better for the round window group. Also, the mean BKB scores for the RW group were higher than the C group between 24 and 30 months post-implantation (p < 0.0013) and at 31-36 months post-implantation (p < 0.0011). for language acquisition; the PLS-4 mean scores for the RW group and the C group between 24 and 30 months post-implantation and at 31-36 months post-implantation were better for the round window group (p < 0.001). The PPVT-4 mean scores for the RW group were also higher than the C group at both durations. for speech production; The mean word intelligibility scores of the DEAP for the RW group were better at 24 to 30 and 31-36 months post-implantation. CONCLUSION: Round window insertion is associated with superior cochlear implantation outcomes regarding speech perception, language acquisition and speech production rather than the standard cochleostomy insertion.