International Consensus Statements on Intraoperative Testing for Cochlear Implantation Surgery.

OBJECTIVES: A wide variety of intraoperative tests are available in cochlear implantation. However, no consensus exists on which tests constitute the minimum necessary battery. We assembled an international panel of clinical experts to develop, refine, and vote upon a set of core consensus statements. DESIGN: A literature review was used to identify intraoperative tests currently used in the field and draft a set of provisional statements. For statement evaluation and refinement, we used a modified Delphi consensus panel structure. Multiple interactive rounds of voting, evaluation, and feedback were conducted to achieve convergence. RESULTS: Twenty-nine provisional statements were included in the original draft. In the first voting round, consensus was reached on 15 statements. Of the 14 statements that did not reach consensus, 12 were revised based on feedback provided by the expert practitioners, and 2 were eliminated. In the second voting round, 10 of the 12 revised statements reached a consensus. The two statements which did not achieve consensus were further revised and subjected to a third voting round. However, both statements failed to achieve consensus in the third round. In addition, during the final revision, one more statement was decided to be deleted due to overlap with another modified statement. CONCLUSIONS: A final core set of 24 consensus statements was generated, covering wide areas of intraoperative testing during CI surgery. These statements may provide utility as evidence-based guidelines to improve quality and achieve uniformity of surgical practice.

A novel coupling quality index to estimate the coupling efficiency in Vibrant Soundbridge.

BACKGROUND: The objective-based methods for intraoperative monitoring have been suggested to assess the coupling and the outcomes of Vibrant Soundbridge (VSB). Although several techniques were proposed, they have not been widely adopted due to their complexity and invasiveness. PURPOSE: This study aimed to investigate the accuracy of a new coupling quality index using an intraoperative ABR threshold via AcoustiAP and its correlation with the perioperative measures. METHODS: This is a prospective study conducted at a tertiary center. The medical records were retrieved for all patients who underwent VSB implantation and had an intraoperative objective assessment for the coupling efficiency. AcoustiAP was used to evaluate the intraoperative ABR thresholds, which were assessed directly after the floating mass transducer (FMT) placement using acoustic CE-Chirp signals. The Vibrogram was used for the postoperative audiological evaluation. A new coupling quality index was calculated based on the intraoperative ABR thresholds. RESULTS: Ten patients were eligible for the present study. The ABR thresholds for good coupling ranged from 35 to 60 dBnHL. The loose coupling thresholds ranged considerably from 40 to 100 dBnHL. Overall, the median intraoperative ABR threshold at good coupling was 42.5 (40-60) dBnHL and 60 (40-100) dBnHL at loose coupling. The analysis showed that there was a significant change in the coupling quality index at the good and loose coupling points (24.3 ± 14 vs 38.8 ± 18.2, respectively, p < 0.001). At a cut-off value of 22.6 dB, the coupling quality index had a sensitivity of 70%  and specificity of 90% for discriminating good and loose coupling. CONCLUSION: This study provides evidence for the utility of intraoperative ABR measurements in predicting the coupling efficiency in patients with VSB. Our results showed that the coupling quality index had an acceptable accuracy in discriminating between good and poor coupling, which can help clinicians optimize the fitting process for individuals and may ultimately lead to improved patient outcomes.

Cochlear implantation in children with auditory neuropathy spectrum disorder: an updated systematic review.

BACKGROUND: The goal of managing auditory neuropathy spectrum disorder (ANSD) is to restore the children's ability to discriminate auditory information. Children who are not making sufficient progress in speech comprehension, and speech and language development after receiving adequate auditory re/habilitation and/or acoustic amplification may be candidates for cochlear implantation (CI). Despite the growing number of published literature on CI outcomes in children with ANSD, the current evidence is primarily based on case reports or retrospective chart reviews some of which had a limited number of children. In addition, the outcomes of CI seem to vary between children with ANSD. Thus, compelling evidence is lacking. This updated systematic review evaluated the speech perception, language, and speech intelligibility outcomes of children with ANSD post-CI. METHODS: An online bibliographic search was conducted in PubMed, Scopus, Web of Science, and CENTRAL databases. We included both interventional and observational studies that assessed the outcomes of the CI in  children with ANSD. RESULTS: Thirty-three studies were included in this systematic review. Several tests were used to assess speech perception following CI in children with ANSD. The findings of this study revealed that  children with ANSD had mean Categories of Auditory Performance scores ranging from 4.3 to 7 post-operatively, this result was better than the pre-operative scores which ranged between 0.4 to 2.5. Likewise, the Infant-Toddler Meaningful Auditory Integration Scale, Phonetically Balanced Kindergarten, and multisyllabic lexical neighborhood test showed clinically relevant improvement after CI. The same findings were reported for language and speech intelligibility scores. One study investigated the quality of life/children satisfaction after CI and showed overall good satisfaction with the outcomes. CONCLUSIONS: The present systematic review suggests that CI is a feasible and effective hearing  rehabilitation modality for children with ANSD. REGISTRATION AND PROTOCOL: PROSPERO ID: CRD42021279140.

Holistic assessment of cochlear implant outcomes using the international classification of functioning disability and health model: data analysis of a longitudinal prospective multicenter study.

PURPOSE: To study outcome after cochlear implantation using the Cochlear Implant (CI) outcome assessment protocol based on the International Classification of Functioning, Disability and Health (ICF) model (CI-ICF). METHODS: Raw data of a prospective, longitudinal, multicenter study was analyzed. Seventy-two CI candidates were assessed preoperatively and six months postoperatively using the CI-ICF protocol. Following tools were used: (1) Work Rehabilitation Questionnaire (WORQ), (2) Abbreviated Profile of Hearing Aid Benefit (APHAB), (3) Audio Processor Satisfaction Questionnaire (APSQ), (4) Speech, Spatial, and Qualities of Hearing Scale (SSQ12), (5) Hearing Implant Sound Quality Index (HISQUI19), (6) Nijmegen CI Questionnaire (NCIQ) (7) pure tone audiometry, (8) speech audiometry, (9) sound localization. RESULTS: There was a significant improvement of speech discrimination in quiet (p = 0.015; p < 0.001) and in noise (p = 0.041; p < 0.001), sound detection (p < 0.001), tinnitus (p = 0.026), listening (p < 0.001), communicating with-receiving-spoken messages (p < 0.001), conversation (p < 0.001), family relationships (p < 0.001), community life (p = 0.019), NCIQ total score and all subdomain scores (p < 0.001). Subjective sound localization significantly improved (p < 0.001), while psychometric sound localization did not. There was no significant subjective deterioration of vestibular functioning and no substantial change in sound aversiveness. CI users reported a high level of implant satisfaction postoperatively. CONCLUSION: This study highlights the positive impact of cochlear implantation on auditory performance, communication, and subjective well-being. The CI-ICF protocol provides a holistic and comprehensive view of the evolution of CI outcomes.

Minimum intraoperative testing battery for cochlear implantation: the international practice trend.

PURPOSE: In cochlear implantation (CI) surgery, there are a wide variety of intraoperative tests available. However, no clear guide exists on which tests must be performed as the minimum intraoperative testing battery. Toward this end, we studied the usage patterns, recommendations, and attitudes of practitioners toward intraoperative testing. METHODS: This study is a multicentric international survey of tertiary referral CI centers. A survey was developed and administered to a group of CI practitioners (n = 34) including otologists, audiologists and biomedical engineers. Thirty six participants were invited to participate in this study based on a their scientific outputs to the literature on the intraoperative testing in CI field and based on their high load of CI surgeries. Thirty four, from 15 countries have accepted the invitation to participate. The participants were asked to indicate the usage trends, perceived value, influence on decision making and duration of each intraoperative test. They were also asked to indicate which tests they believe should be included in a minimum test battery for routine cases. RESULTS: Thirty-two (94%) experts provided responses. The most frequently recommended tests for a minimum battery were facial nerve monitoring, electrode impedance measurements, and measurements of electrically evoked compound action potentials (ECAPs). The perceived value and influence on surgical decision-making also varied, with high-resolution CT being rated the highest on both measures. CONCLUSION: Facial nerve monitoring, electrode impedance measurements, and ECAP measurements are currently the core tests of the intraoperative test battery for CI surgery.

Early activation after cochlear implantation: a systematic review.

PURPOSE: To systematically review the outcomes of early activation following cochlear implantation (CI) based on the findings from different studies in the literature. METHODS: A comprehensive search strategy was conducted through different databases to identify relevant articles. Our outcomes included impedance levels, rates of complications, hearing and speech perception performance, and patients' satisfaction levels. RESULTS: The total number of included studies in this systematic review is 19, which recruited 1157 patients, including 857 who underwent early activation following CI. Seventeen studies investigated impedance levels or feasibility rates of early activation approaches. Most of these studies (n = 10) reported that mean impedance levels remarkably decreased within the first day-to-month (first measurement) post-activation. In addition, all 17 studies showed that impedance levels finally normalize and become comparable with intraoperative levels or the conventional activation group. Seventeen studies reported the occurrence of complications in their population. Ten of these studies indicated that none of their patients developed any post-operative complications after early activation. Seven studies reported the development of some minor complications, including pain 9.2% (28/304), infection 4.7% (13/275), swelling 8.2% (25/304), vertigo 15.1% (8/53), skin hyperemia 2.2% (5/228), and others 16.4% (9/55). Hearing and speech perception was assessed in six studies, which showed a remarkable improvement in their patients. Three studies investigated patients' satisfaction and showed high satisfaction levels. Only one report investigated the economic advantages of early activation. CONCLUSION: Early activation is safe and feasible and does not impact the hearing and speech outcomes of the patients undergoing CI procedures.

Comparison of temporalis muscle fascia and cartilage grafts for primary type 1 tympanoplasty: a meta-analysis of randomized controlled trials.

PURPOSE: To compare the efficacy and safety of temporalis fascia (TF) with cartilage grafts for primary type 1 tympanoplasty in chronic otitis media (COM) patients. METHODS: Computerized search was performed in MEDLINE, Embase, and CENTRAL. Eligible for inclusion were randomized controlled trials (RCTs) comparing TF and cartilage grafts in individuals with non-cholesteatoma COM and intact ossicles requiring type 1 tympanoplasty. Primary outcomes were graft success and hearing improvement, measured by the air-bone gap (ABG) closure. The secondary outcome was the occurrence of complications. Standardized mean differences (SMD) and odds ratios (OR) with 95% confidence intervals were calculated. RESULTS: Eighteen RCTs that enrolled 1273 participants were found eligible. Data were reported at follow-up periods ranging from 6 weeks to 24 months. The pooled effect estimate revealed a higher and statistically significant graft success favoring cartilage grafts at 12 months (OR = 2.24, 95% CI 1.33-3.78) and 24 months (OR = 2.96, 95% CI 1.18-7.43). There was no significant difference between both grafts in post-operative ABG closure across all follow-up periods (6 weeks to 12 months). CONCLUSIONS: Compared to TF, primary type 1 cartilage tympanoplasty offers better graft uptake rates and comparable postoperative hearing outcomes for COM patients.

Cochlear implantation in common cavity deformity: a systematic review.

PURPOSE: Cochlear implantation became a valid hearing rehabilitation option in common cavity deformity. This study aimed to assess the audiological and speech outcomes of cochlear implantation in common cavity deformity patients and to address the surgical aspect used in this population. METHODS: A comprehensive systematic literature review based on preferred reporting items for systematic reviews and meta-analyses (PRISMA) guideline from database inception through April 2020. Eighteen published articles including 138 patients with common cavity deformity met the inclusion criteria. These articles studied the surgical techniques and the audiological outcomes of cochlear implantation in patients with common cavity deformity in English language. RESULTS: Trans-mastoid labyrinthotomy was the common surgical approach in these patients. The average speech intelligibility rating and categories of auditory performance scores in common cavity deformity were lower than in normal cochlea subjects (p < 0.05), and non-significant (p > 0.05) compared with other types of inner ear malformations. CONCLUSION: Patients with common cavity deformity who underwent cochlear implantation showed a beneficial audiological and speech outcome. However, their performance is highly variable. Therefore, pre-operative counseling of the parents is necessary. The surgical approaches should be individualized according to clinical, radiological, and surgical findings.

Cochlear implantation in adults and pediatrics with enlarged vestibular aqueduct: a systematic review on the surgical findings and patients' performance.

PURPOSE: Cochlear implantation (CI) has been considered a safe and effective management option for patients with severe to profound hearing loss. Patients with enlarged vestibular aqueduct (EVA) could be challenging with some variations in surgical approaches, intraoperative surgical notes, and clinical outcomes. This study aimed to  review the surgical and clinical outcomes of cochlear implantation among patients with EVA. MATERIALS AND METHODS: A systematic literature search was carried out in five major databases. All original studies reporting cochlear implantation in patients with EVA were included for qualitative data synthesis. The risk of bias was independently assessed through the National Intuitional of Health tool. The review protocol was registered in PROSPERO (reference number: CRD42021225900). RESULTS: A total of 34 studies with 4035 subjects were included. Of them, 853 (21.14%) had EVA and underwent CI. Mondini malformation was the most frequently associated anomaly (n = 78, 11.1%). Unilateral implantation was performed in 258 cases while bilateral in 119 subjects. Postoperative complications included CSF/perilymph gusher (n = 112), CSF oozing (n = 18), and partial electrode insertion (n = 6). Closing the cochleostomy with temporalis fascia, muscle, connective tissue, or fibrin glue was the most frequently reported approach to manage CSF/perilymph gusher (n = 67, 56.7%) while packing was performed in six patients. CONCLUSION: Patients with EVA demonstrated audiometric and speech performance improvement after CI. However, many patients had intra- or postoperative complications. Further research is needed as the outcomes may be affected by associated temporal bone pathology, the timing of implant, and hearing condition.

Performance of cochlear implant recipients fitted with triphasic pulse patterns.

PURPOSE: To assess the effect of triphasic pulse pattern stimulation strategy on the audiological performance of cochlear implant recipients with unintended facial nerve stimulation (FNS), and to compare the audiological and speech outcomes before and after switching to triphasic stimulation. METHODS: A retrospective study of patients who have changed their fitting maps from biphasic to triphasic pulse pattern stimulation because of FNS after cochlear implantation (CI). All identified patients with FNS after CI from 2017 to 2019 were included in this study. The medical records of 11 patients (16 ears) were queried for demographic and radiological data, pure tone audiometry, speech reception thresholds, speech discrimination score at 65 dB, maximum comfortable levels, thresholds, and dynamic range. Then, these parameters were compared in the two conditions, biphasic and triphasic. RESULTS: Using triphasic pulse stimulation only or combined with switch-off of few channels, complete resolution of FNS was achieved. Triphasic pulse pattern stimulation was associated with better speech discrimination scores (75.25 ± 26.13%) compared to the biphasic pulse (58.25 ± 26.13%). This triphasic strategy also showed higher maximum comfortable levels (36.62 ± 1.63 qu) than biphasic strategy (31.58 ± 2.5 qu). Moreover, the dynamic range was wider using triphasic pulse strategy. In general, the triphasic pulse pattern resulted in successful suppression of facial nerve stimulation with suitable maximum comfortable levels and better speech discrimination. CONCLUSION: Triphasic pulse pattern stimulation is an appropriate tool in controlling FNS following cochlear implantation with wider dynamic range. We recommend that all patients with facial nerve stimulation after CI surgery be switched to a triphasic pulse program prior to considering further surgery.

Influence of Cochlear Anatomy on Intraoperative Electrically Evoked Compound Action Potentials.

Objective: The electrically evoked compound action potential (ECAP) is an objective measure to indirectly assess spiral ganglion neurons. The ECAP provides inputs about the prognoses of cochlear implant (CI) recipients. Several factors such as cochlear morphology can affect ECAP measurements. This study aims to investigate the variation effect of cochlear parameters on intraoperative ECAP thresholds. Methods: This is a retrospective study on patients who underwent CI surgery with normal inner ear morphology at our center between 2017 and 2023. Cochlear anatomical parameters, including diameter (A value), width (B value), and height (H value), as well as cochlear duct length (CDL), were measured pre-operatively using OTOPLAN software (Version 3.0). Cochlear implant intraoperative objective measures were also collected. The correlation between the cochlear parameters and intraoperative objective measures was studied. Results: A total of 45 patients underwent cochlear implantation. The mean age was 2.4 ± 0.9 years. The mean CDL and cochlear coverage values were 33.2 ± 2.0 mm and 76.0 ± 5.7%, respectively. The ECAP threshold increased toward basal electrodes, with ECAP values as follows: apical 13.1 ± 3.8; middle 14.3 ± 3.7; and basal 15.6 ± 4.8. Additionally, the A, B, and H values showed a positive correlation with ECAP thresholds in different cochlear regions. The B value showed a significant moderate correlation with ECAP thresholds in the middle and basal electrodes but not in the apical electrodes. Conclusions: Cochlear anatomical parameters correlate with intraoperative ECAP thresholds. The B value showed a significant association with ECAP thresholds in the middle and basal electrodes. These findings could delineate the impact of the B value in CI and optimize electrode selection. Further research is required to study this correlation and its impact on postoperative outcomes.

Cochlear implantation in pediatrics: Impact of newborn hearing screening on intervention time.

OBJECTIVES: The newborn hearing screening (NHS) program was globally established for early hearing loss (HL) identification and intervention. Early intervention is essential to minimize or prevent the negative consequences of HL. In Saudi Arabia, the NHS was officially implemented in 2016. Currently, its impact on the timing of cochlear implantations (CIs) in Saudi Arabia remains unclear, and information on potential hospital-related delays affecting early implantation is lacking. Thus, this study aimed to evaluate the effect of implementing the NHS on age at CI in children with prelingual deafness in a CI center in Saudi Arabia, and to evaluate the hospital timing in the CI process. METHODS: All pediatric CI users who presented for the first time to the CI committee (CIC) at a tertiary center and received their implants between 2015 and 2022 were enrolled in this study. Date of birth (DOB), date of presentation to the CI committee (DOCIC), and date of CI surgery (DOCIS) were retrospectively reviewed. RESULTS: In total, 304 CI children were included in the analysis. Approximately 55 % of the children (n = 167) were screened for HL through the NHS, whereas 45 % of the children (n = 137) were born before the launch of the NHS. Both age at the presentation to the CIC (i.e. difference between DOCIC and DOB) and age at implantation (i.e. difference between DOCIS and DOB) were significantly earlier in children who were screened for HL through the NHS than those who were not screened (P < 0.0001). The time difference between the DOCIC and DOCIS was not significantly different between the screened and unscreened children (P > 0.05). CONCLUSION: The implementation of the NHS in the tertiary center has a significant positive effect on age at presentation to the CIC and age at implantation, but not on the actual CI surgery. Further research is needed to reduce the hospital delays before the actual surgery in order to increase the likelihood of children receiving implantation early in their life.

Validation of the Arabic language version of the Audio Processor Satisfaction Questionnaire (APSQ) for hearing implant users.

OBJECTIVE: Audio processors (AP) are the external components of hearing implants. User satisfaction with the performance and comfort of their AP is a critical factor in ensuring daily use, which leads to improved hearing outcomes. The aim of this study was to construct and validate an Arabic language translation of the APSQ for use among Arabic-speaking clinicians and patients. DESIGN: The original APSQ was translated into the Arabic language using cross-cultural adaptation measures. The final questionnaire was administered to CI users in electronic form. STUDY SAMPLE: 117 CI users (64 female) participated. A total of 179 ears were assessed. RESULTS: High levels of satisfaction with audio processors were observed among CI users. Item and scale analyses indicate that this version of the APSQ measure a homogeneous and valid construct. CONCLUSION: The Arabic version of the APSQ captures user satisfaction with hearing implant audio processors.

A novel method for evaluating mastoid defect regrowth after cochlear implantation.

This retrospective study examined mastoid defects resulting from cochlear implant (CI) surgery and their potential for spontaneous regrowth across different age groups. Spontaneous closure of mastoid defects has been observed in certain CI patients during revision surgery or through post-operative temporal bone computer tomography (TB-CT). The analysis encompassed 123 CI recipients, comprising 81.3% children and 18.7% adults, who underwent post-operative TB-CT scans. Using image adjustment software, the study measured mastoid defect areas and found a significant reduction in children's defects between the initial and subsequent scans. Notably, mastoid defect areas differed significantly between children and adults at both time points. Furthermore, the analysis revealed significant correlations between mastoid defect areas and the age at implantation as well as the time elapsed since the CI surgery and the first CT scan. This study provides valuable insights for evaluating CI patients scheduled for revision surgery by assessing potential surgical challenges and duration. Furthermore, it may have a pivotal role in evaluating patients who experience postauricular swelling subsequent to CI surgery.

Cochlear Implantation: Long-Term Effect of Early Activation on Electrode Impedance.

Objectives: The growing adoption of cochlear implants (CIs) necessitates understanding the factors influencing long-term performance and improved outcomes. This work investigated the long-term effect of early activation of CIs on electrode impedance in a large sample of CI users at different time points. Methods: A retrospective study on 915 ears from CI patients who were implanted between 2015 and 2020. According to their CI audio processor activation time, the patients were categorized into early activation (activated 1 day after surgery, n = 481) and classical activation (activated 4 weeks after surgery, n = 434) groups. Then, the impact of the activation times on the electrode impedance values, along the electrode array contacts, at different time points up to two years was studied and analyzed. Results: The early activation group demonstrated lower impedance values across all the electrode array sections compared to the classical activation at 1 month, 1 year, and 2 years post-implantation. At 1 month, early activation was associated with a reduction of 0.34 kΩ, 0.46 kΩ, and 0.37 kΩ in the apical, middle, and basal sections, respectively. These differences persisted at subsequent intervals. Conclusions: Early activation leads to sustained reductions in the electrode impedance compared to classical activation (CA), suggesting that earlier activation might positively affect long-term CI outcomes.

Advancing Cochlear Implant Programming: X-ray Guided Anatomy-Based Fitting.

BACKGROUND: Anatomy-based fitting (ABF) is a new research area in the field of cochlear implants (CIs). Despite the reported benefits and acceptable levels of ABF among CI recipients, some limitations remain, like the postoperative computed tomography (CT) scan, which is preferred for confirming electrode array insertion. OBJECTIVE: This study aimed to investigate the feasibility of using plain film radiography (X-ray) for postoperative electrode detection and for building ABF as an alternative to CT. METHODS: A total of 53 ears with CI were studied. All cases had routine post-insertion X-rays in the cochlear view and additionally underwent postoperative CT. The insertion angles and center frequencies measured by two independent observers were compared for each imaging modality. The angular insertion depth and center frequencies resulting from the X-ray and CT scans were then compared. RESULTS: No significant differences were observed between the X-ray- and CT-measured angles for the electrode contacts. Radiographic measurements between the two readers showed an almost perfect (≥0.8) or substantial (0.71) intraclass correlation coefficient along the electrode contacts. X-ray images showed a mean difference of 4.7 degrees from CT. The mean semitone deviation of the central frequency between the CT and X-ray images was 0.6. CONCLUSIONS: X-ray imaging provides a valid and easy-to-perform alternative to CT imaging, with less radiation exposure and lower costs. The radiographs showed excellent concordance with the CT-measured angular insertion depth and consequently with the central frequency for most electrode contacts. Therefore, plain X-ray could be a viable alternative in building ABF for the CI recipients.

The Chronological Evolution of Cochlear Implant Contraindications: A Comprehensive Review.

Cochlear implantation has emerged as a transformative intervention in addressing profound hearing loss, offering a paradigm shift in auditory rehabilitation for individuals with restricted auditory function. Throughout its history, the understanding of contraindications for cochlear implant (CI) surgery has evolved significantly. This review comprehensively analyzes the chronological advancements in the understanding of CI contraindications, examining studies conducted from historical timelines to the present. Recent research has revealed significant developments in the field, prompting a reevaluation of established criteria and resulting in expanded indications for CI. The chronological evolution of contraindications underscores the transformative nature of the field, offering potential improvements in outcomes and enhancing the quality of life for individuals with profound hearing loss. In conclusion, this narrative review emphasizes the dynamic nature of the field, where the reevaluation of contraindications has created new opportunities and broader indications for CI. The emerging prospects, including improved outcomes and enhanced quality of life, hold promise for individuals with profound hearing loss.

Cochlear implantation: Predicting the scala tympani volume of the pediatric recipients.

OBJECTIVES: The main aim of this study was to estimate the volume of the Scala Tympani (ST) of our pediatric cochlear implant (CI) recipients from the computed tomography (CT) images. Then, to study the association between ST volume and both demographic characteristics and cochlear parameters. METHODS: A retrospective study on the CT scans of pediatric CI patients at a tertiary referral CI center. Congenital or acquired cochlear defects were excluded. Two reviewers, with the same level of experience, blindly measured the main cochlear parameters and studied its anatomy. Then, the interrater reliability was tested to measure any differences between the two readings. After that, the ST volume of the included patients was calculated and analyzed. Furthermore, the correlations between the main cochlear parameters and ST volume were studied to propose a formula for estimating the ST volume from the cochlear duct length (CDL). RESULTS: The mean predicted ST volume among our pediatric CI recipients was 38.51 ± 5.54 µl (range; 24.47-52.57 µl). The statistical analysis revealed that all cochlear parameters (A, B, H, and CDL values) could be significant predictors of the ST volume (p=<0.0001). CONCLUSION: The main cochlear parameters along with the CDL are positively linked to the ST volume. There are considerable differences in cochlear size and scala tympani volume among our pediatric population. These findings confirm the importance of pre-operative planning for proper electrode array selection.

Enhancing cochlear duct length estimation by incorporating second-turn parameters.

Estimating insertion depth, cochlear duct length (CDL), and other inner ear parameters is vital to optimizing cochlear implantation outcomes. Most current formulas use only the basal turn dimensions for CDL prediction. In this study, we investigated the importance of the second turn parameters in estimating CDL. Two experienced neuro-otologists blindly used segmentation software to measure (in mm) cochlear parameters, including basal turn diameter (A), basal turn width (B), second-turn diameter (A2), second-turn width (B2), CDL, first-turn length, and second-turn length (STL). These readings were taken from 33 computed tomography (CT) images of temporal bones from anatomically normal ears. We constructed regression models using A, B, A2, and B2 values fitted to CDL, two-turn length, and five-fold cross-validation to ensure model validity. CDL, A value, and STL were longer in males than in females. The mean B2/A2 ratio was 0.91 ± 0.06. Adding A2 and B2 values improved CDL prediction accuracy to 86.11%. Therefore, we propose a new formula for more accurate CDL estimation using A, B, A2, and B2 values. In conclusion, the findings of this study revealed a notable improvement in the prediction of two-turn length (2TL), and CDL by clinically appreciable margins upon adding A2 and B2 values to the prediction formulas.

Cochlear Implantation: The use of OTOPLAN Reconstructed Images in Trajectory Identification.

OBJECTIVES: This study aimed to define the best electrode trajectory line in cochlear implant (CI) surgery using the OTOPLAN (otology planning software) reconstructed 3D model and to investigate the surgical distance of the retro-facial approach as a direct access to the round window. METHODS: Computed tomography (CT) scans of the normal temporal bone were included for analysis in this study. OTOPLAN reconstruction was used to build 3D models with specific ear structures for study analysis. RESULTS: Twenty-five scans were included; the average age at the time of CT scan was 6.8±12 years. Twelve scans (48%) were right-sided and thirteen (52%) were left-sided. The best trajectory line to the round window was identified in all scans. The retro-facial approach was the optimal approach for 52% of cases (13/25). In all scans, the safe distance from the facial nerve were in favor of the retro-facial approach (P = 0.0011). CONCLUSION: The OTOPLAN reconstructed imaging provided a good analysis of the retro-facial approach and helped in planning the surgical trajectory line towards the round window. Additionally, calculation of the surgical distance can help the surgeon compare the retro-facial approach to the standard facial recess for preoperative planning. These findings may help in robotic surgery.