Faculty Bibliography

OBJECTIVE:To better understand the distance relationship of the stapes to the round window, to assist in intraoperative round window identification. STUDY DESIGN/METHODS:Retrospective review of CT temporal bone imaging and multiplanar image reformat analysis. SETTING/METHODS:Tertiary referral center. PATIENTS/METHODS:Patients above 18 years of age who underwent cochlear implantation between January 2020 and April 2025 and had preoperative computed tomography (CT) imaging of the temporal bone. Patients were excluded if they had prior surgical procedures that could distort the stapes superstructure (eg, stapedectomy) or if image quality/resolution precluded adequate visualization of the stapes crus. INTERVENTION/METHODS:None. MAIN OUTCOME MEASURE/METHODS:Prediction accuracy of the stapes intercrural width to locate the level of the round window. RESULTS:There were 102 ears that were studied, including 51 (50%) left and 51 (50%) right ears. The average measured intercrural width was 2.1 mm (SD: 0.17 mm). The maximum intercrural distance was found to be 2.6 mm, and the minimum distance was 1.7 mm. In all 102 (100%) ears, the intercrural distance of the stapes accurately predicted the level of the RW on image analysis. CONCLUSION/CONCLUSIONS:The stapes intercrural width can be utilized as an accurate predictor of the round window level and is a simple and intuitive intraoperative tool surgeons can utilize to safely gain access to the cochlea.

OBJECTIVE/UNASSIGNED:We sought to consolidate the anatomical findings from radiologic research and prior surgical literature to develop a stepwise surgical approach utilizing cadaveric specimens which can serve to improve the accuracy and scalability of surgical apical cochleostomies in the future. METHODS/UNASSIGNED:Cadaveric temporal bone dissections, with subsequent image documentation and distance measurements to confirm surgical accuracy. RESULTS/UNASSIGNED:All four temporal bones (100%) that were drilled utilizing the newly developed surgical approach had an accurately placed apical cochleostomy. No inadvertent entry into the middle turn of the cochlea occurred. There was no violation of the labyrinthine facial nerve, or carotid artery. CONCLUSIONS/UNASSIGNED:Preliminary findings are promising for the described steps to achieve a substantial improvement in apical cochleostomy accuracy, with reduced trauma compared to historically taught techniques.

OBJECTIVE:Observe if metal artifact reduction (MAR) techniques applied to magnetic resonance imaging (MRI) performed on patients with cochlear implants (CI) or auditory brainstem implants (ABI) improves image quality. STUDY DESIGN/METHODS:Retrospective review. SETTING/METHODS:Tertiary care center. PATIENTS/METHODS:Patients with auditory implants who underwent clinical MRI before and after the application of MAR techniques previously described. INTERVENTIONS/METHODS:From September 2022 to March 2023, patients who underwent brain or internal auditory canal (IAC) MRI with and without MAR were identified. Sequences included T1 and T2 weighted with turbo-spin-echo (TSE) correction and fluid-attenuation inversion recovery (FLAIR). Images were analyzed for visualization of intracranial structures by two neuroradiologists. MAIN OUTCOME MEASURES/METHODS:Visibility of 14 structures graded on a four-point Likert scale. Average scores per structure and sequence were compared using paired two-tailed t-tests and change in mode score. RESULTS:Ten patients underwent pre- and post-MAR MRI. Six had a unilateral CI, three had a unilateral ABI, and one had an ABI and CI. Three patients had four devices with the internal magnet removed for both scans. All structures had significantly improved visibility on post-MAR scan except ipsilateral parietal and occipital lobes and contralateral inner ear. Mode score increased from 2 to 4 for the ipsilateral occipital lobe and from 3 to 4 for the ipsilateral semicircular canals, brainstem, and cerebellar peduncles. Significant improvement was seen in all sequences except for ipsilateral structures on T1w axial precontrast and contralateral structures on T1w coronal postcontrast. ABIs did not improve as much as CIs because they scored better on the pre-MAR scan. CONCLUSIONS:MAR techniques improve image quality for patients with MRI-compatible implants with magnets. Benefits may be more evident in CIs than ABIs.

OBJECTIVES/OBJECTIVE:To assess a decade of experience of treating patients with high hearing risk cerebellopontine angle (CPA) epidermoid lesions and examine factors influencing postoperative outcomes, particularly hearing preservation. STUDY DESIGN/METHODS:Retrospective chart review. SETTING/METHODS:Single tertiary-referral center. PATIENTS/METHODS:Adults with CPA epidermoid lesions who presented with hearing loss or evidence of lesion involving vestibulocochlear nerve. INTERVENTIONS/METHODS:The studied intervention was microsurgical resection. MAIN OUTCOME MEASURES/METHODS:Main outcome measures included extent of resection, hearing preservation rate for patients with postoperative audiograms, and disease progression. RESULTS:Twenty-three adults with an average tumor volume of 15.63 ± 16.2 cm3 were included. Five lesions (22%) involved the full internal auditory canal (IAC), 11 (48%) had partial involvement, and 5 (22%) were IAC sparing. Most patients with IAC involvement (88%) had circumferential invasion of the canal. Patients underwent either a retrosigmoid (18, 79%) or combined retrolabyrinthine transpetrosal approach (5, 22%), and gross total resection was achieved in most cases (13, 57%). Of 12 patients with postoperative audiograms, 10 (83%) had preoperative hearing preserved. There was no statistically significant change in hearing scores with treatment based on preoperative extent of IAC involvement. Ten patients (43%) had residual lesions postoperatively, and 6 exhibited progression. One patient ultimately required reoperation 6 years after initial surgery. CONCLUSIONS:Preoperative hearing was preserved in the majority of the patients who underwent resection of CPA epidermoids via a retrosigmoid or transpetrosal approach. CPA epidermoids often invaded the IAC; however, degree of invasion was not associated with hearing outcomes.

OBJECTIVE:To compare cochlear implant (CI) speech perception outcomes in patients with sporadic vestibular schwannoma (VS) managed with observation, radiosurgery, or microsurgery. STUDY DESIGN/METHODS:Retrospective review. SETTING/METHODS:Eleven tertiary academic medical centers. PATIENTS/METHODS:One hundred patients with sporadic VS who received an ipsilateral CI. INTERVENTIONS/METHODS:Ipsilateral cochlear implantation. MAIN OUTCOME MEASURES/METHODS:Pure-tone thresholds, monosyllabic speech perception testing scores, and rates of open-set speech acquisition. RESULTS:Of the 100 patients studied, 54 underwent microsurgery, 26 underwent radiosurgery, 19 continued observation, and 1 underwent multimodal therapy. Among all patients, the median post-implantation pure-tone average was 31 dB (interquartile range [IQR] 25-39 dB) and the median monosyllabic speech perception score was 30% (IQR 0-60%) at a median of 12 months (IQR 5-25 months) post-implantation. Patients who were managed with microsurgery (median speech perception score 11%, IQR 0-52%) exhibited poorer implant outcomes overall compared with those managed with observation (median speech perception score 52%, IQR 40-72%) or radiosurgery (median speech perception score 30%, IQR 16-60%). Open-set speech perception was achieved in 61% of patients managed with microsurgery, 100% with observation, and 80% with radiosurgery. In a multivariable setting, those managed with observation (p = 0.02) or who underwent radiosurgery (p = 0.04) were significantly more likely to achieve open-set speech perception compared with patients who underwent microsurgery. CONCLUSIONS:Cochlear implants offer benefit in selected patients with sporadic VS. Although achieved in over half of people after microsurgery, open-set speech perception is more reliably attained in patients who are treated with observation or radiosurgery compared with microsurgical resection. These data may inform patient counseling and VS tumor management in people who may benefit from implantation.

OBJECTIVE:To better understand cochlear implant (CI) performance after reimplantation with a different device manufacturer. STUDY DESIGN/METHODS:Multisite retrospective review. SETTING/METHODS:Tertiary referral centers. PATIENTS/METHODS:Patients older than 4 years who received a CI and subsequently underwent CI reimplantation with a different manufacturer over a 20-year period. INTERVENTION/METHODS:Reimplantation. MAIN OUTCOME MEASURE/METHODS:The primary outcome was difference in the best CNC score obtained with the primary CI, compared with the most recent CNC score obtained after reimplantation. RESULTS:Twenty-nine patients met the criteria at three centers. The best average CNC score achieved by adult patients after primary cochlear implantation was 46.2% (n = 16), measured an average of 14 months (range: 3-36 mo) postoperatively. When looking at the most recent CNC score of adult patients before undergoing reimplantation, the average CNC score dropped to 19.2% (n = 17). After reimplantation, the average 3- to 6-month CNC score was 48.3% (n = 12), with most recent average CNC score being 44.4% (n = 17) measured an average of 19 months (range: 3-46 mo) postoperatively. There was no statistically significant difference (p = 0.321; t11 = 0.48) identified in performance between the best CNC score achieved by adult patients after primary cochlear implantation, and the most recent score achieved after reimplantation (n = 12). Analysis of prerevision and postrevision speech performance was not possible in pediatric patients (<18 yr old) because of differences in tests administered. CONCLUSION/CONCLUSIONS:Patients undergoing reimplantation with a different manufacturer achieved CNC score performance comparable to their best performance with their original device.

OBJECTIVE:To characterize transimpedance matrix (TIM) heatmap patterns in patients at risk of labyrinthine abnormality to better understand accuracy and possible TIM limitations. STUDY DESIGN/METHODS:Retrospective review of TIM patterns, preoperative, and postoperative imaging. SETTING/METHODS:Tertiary referral center. PATIENTS/METHODS:Patients undergoing cochlear implantation with risk of labyrinthine abnormality. INTERVENTION/METHODS:None. RESULTS:Seventy-seven patients were evaluated. Twenty-five percent (n = 19) of patients had a TIM pattern variant identified. These variants were separated into 10 novel categories. Overall, 9% (n = 6) of electrodes were malpositioned on intraoperative x-ray, of which 50% (n = 3) were underinserted, 17% (n = 1) were overinserted, 17% (n = 1) had a tip foldover, and 17% (n = 1) had a coiled electrode. The number of patients with a variant TIM pattern and normal x-ray was 18% (n = 14), and the number of patients with normal TIM pattern and malposition noted on x-ray was 3% (n = 2; both were electrode underinsertions that were recognized due to open circuits and surgical visualization).A newly defined skip heat pattern was identified in patients with IP2/Mondini malformation and interscalar septum width <0.5 mm at the cochlear pars ascendens of the basal turn. CONCLUSIONS:This study defines novel patterns for TIM heatmap characterization to facilitate collaborative and comparative research moving forward. In doing so, it highlights a new pattern termed skip heat, which corresponds with a deficient interscalar septum of the cochlea pars ascendens of the basal turn in patients with IP2 malformation. Overall, the data assist the surgeon in better understanding the implications and limitations of TIM patterns within groups of patients with risk of labyrinthine abnormalities.

OBJECTIVE/UNASSIGNED:To better characterize the cochlear apex in relation to surgically relevant landmarks to guide surgeons and improve procedural success of apical electrode placement. STUDY DESIGN/UNASSIGNED:Retrospective image analysis. SETTING/UNASSIGNED:Tertiary referral center. PATIENTS/UNASSIGNED:Cochlear implant recipients with available preoperative computed tomography (CT) imaging. INTERVENTION/UNASSIGNED:None. MAIN OUTCOME MEASURE/UNASSIGNED:Cochlear dimensions and cochlear apex distance measures to surgically relevant middle ear landmarks and critical structures. RESULTS/UNASSIGNED:Eighty-two temporal bone CT scans were analyzed utilizing multiplanar reformats. The average lateral width of promontory bone over the cochlear apex was 1.2 mm (standard deviation [SD], 0.3). The anteroposterior distance from the round window (avg, 4.2 mm; SD, 0.5), oval window (avg, 3.3 mm; SD, 0.3), cochleariform process (avg, 2.3; SD, 0.5), and superior-inferior distance from the cochleariform process (avg, -0.9; SD, 0.8) to the cochlear apex were measured. The relationship of the cochlear apex to critical structures was highly variable.A newly developed stapes vector was created and found to mark the posterior/superior boundary of the apex in 94% of patients. When a vector parallel to the stapes vector was drawn through the round window, it marked the anterior/inferior boundary of the cochlear apex in 89% of patients. CONCLUSIONS/UNASSIGNED:This study assists in characterizing cochlear apex anatomy and its relation to surrounding structures as a means of improving procedural accuracy and reducing trauma during apical cochleostomy. Understanding both distance relationships and expected boundaries of the apex could help to inform future surgical approaches.

OBJECTIVE:To assess the safety of cochlear implants (CIs) in children under 9 months of age to better understand expected postoperative complication rates, and to provide a preliminary look at efficacy. STUDY DESIGN/METHODS:Single-center retrospective review. SETTING/METHODS:Tertiary referral center. PATIENTS/METHODS:Children 5 to 8 months of age who received a CI between 2011 and 2021. INTERVENTIONS/METHODS:Therapeutic-CI. MAIN OUTCOME MEASURES/METHODS:The primary outcome was 6-month postoperative complication rate. Secondary outcomes included length of stay, device explantation/reimplantation, rehabilitation supports, and hearing and language outcomes. Complications of children implanted under than 9 months of age was compared with a cohort of children implanted 9 to 18 months of age between the years 2011 and 2016 using a chi-squared test (p < 0.05). RESULTS:One hundred six children under 9 months of age were implanted (204 CIs) at a mean age of 6.6 months (range: 5-8). Postoperative complications occurred in 28 patients (26%) and were often minor. There were no mortalities. There was no statistically significant difference in complications, including reimplantation rates, between patients implanted under 9 months of age and those implanted 9 to 18 months of age. Speech discrimination outcomes were excellent, and mean spoken language outcomes were near normative for typically developing children. CONCLUSIONS:Cochlear implantation can be a safe and effective treatment option for children 5 to 8 months of age. Early hearing screening and referral for infants to receive appropriate intervention will continue to play a critical role in optimizing speech and language outcomes.