Carlson, Matthew L.

Objectives Evaluate the training background of surgeons performing high volumes of cochlear implants (CIs) and estimate the ratio of providers trained in otology/neurotology (O&N) to the number of traditional CI candidates and audiologists. Methods A retrospective review of US surgeon registration data from a single CI manufacturer was performed to determine CI volume based on surgeon training. The prevalence of traditional candidates for CIs was estimated from US census population data and compared with the number of O&N providers. The ratio of audiologists to O&N providers was estimated from the Bureau of Labor and Statistics and American Speech‐Language‐Hearing Association databases. Results From 2021 to 2023, a mean of 88% of providers performing ≥25 CIs per year and 90% performing ≥40 per year had training in O&N. All surgeons registering ≥100 implants per year were O&N providers. The mean percentage of O&N providers performing ≥25 CIs per year and ≥ 40 per year was higher than the percentage of General and Pediatric Otolaryngology providers performing the same volume: mean difference = 76%, p < 0.001 and mean difference = 79%, p < 0.001, respectively. The mean estimated prevalence of traditional CI candidates per O&N provider is 3,354 with an estimated mean of 32 audiologists (3.5 trained in CIs) per O&N provider. Conclusion 88% of high‐volume CI surgeons have fellowship training in O&N. To meet the current state of CI underutilization and anticipated growing population of CI candidates, we propose increasing the surgical capacity of O&N providers and the number of surgeons proficient in CIs. Level of Evidence NA Laryngoscope , 135:2146–2153, 2025

AbstractObjectiveLimited evidence guides the optimal timing of treatment after the detection of tumor growth during the observation of sporadic vestibular schwannoma (VS). The current work aimed to inform the timing of radiosurgical intervention based on an analysis of patient outcomes among those who ultimately failed stereotactic radiosurgery (SRS) and underwent salvage microsurgery.Study DesignA historical cohort study.SettingSeven centers across the United States and Norway.MethodsAdults with sporadic VS who underwent salvage microsurgery following failed primary SRS were included. The primary outcome of interest was the association between tumor size at the time of primary SRS and the ability to achieve gross total resection (GTR) and maintain postoperative House–Brackmann (HB) facial nerve grade I at the last follow‐up after salvage microsurgery.ResultsAmong 96 patients, the median (interquartile range [IQR]) cerebellopontine angle (CPA) tumor size at primary SRS was 14.5 mm (10.0‐19.0). Each 1‐mm increase in CPA tumor size at the time of primary SRS was associated with a 13% increased likelihood of near‐total/subtotal resection or most recent postoperative HB grade >I (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.05‐1.21, P = .001), with an optimal tumor size threshold to distinguish this outcome of 12 mm of CPA extension (c‐index 0.73). Similarly, for each 1‐mm increase in CPA tumor size at the time of primary SRS, a 9% increase in any postoperative complication with salvage microsurgery was observed (OR 1.09, 95% CI 1.02‐1.15, P = .009).ConclusionCorroborated by size threshold surveillance data informing the timing of primary microsurgical resection, the current study suggests that VS outcomes are optimized when primary radiosurgical intervention is undertaken on growing tumors when they harbor 10–15 mm of cerebellopontine angle extension or less.

Objective To analyze the use of electrical field imaging (EFI) in the detection of extracochlear electrodes in cochlear implants (CI) Study Design Retrospective cohort study Setting Tertiary academic medical center Methods EFI patterns from 6 recipients with extracochlear electrodes were compared with 10 recipients with all intracochlear electrodes to identify differences in EFI patterns between these two groups. For the extracochlear group, EFI patterns were analyzed using two methods: visual inspection and calculation of the average impedance difference (AID) between specific EFI curves. These results were then compared with information from CT and plain film imaging, surgical notes, and audiology tests to confirm the placement of the electrodes in each recipient. Results An average AID of 0.06 kΩ was calculated from the EFI patterns for recipients with complete electrode insertion, whereas an average AID of 0.15 kΩ was calculated from the EFI curves measured for the extracochlear electrodes. Visual analysis of the EFI impedance curves for extracochlear electrodes showed a distinct separation from those measured for intracochlear electrodes. Based on AID analysis and visual inspection the EFI, patterns were in close agreement with the number of extracochlear electrodes detected based on either imaging, intraoperative surgical note, or audiological findings. Conclusion EFI is a noninvasive, inexpensive, and time-efficient measurement that can be used to detect extracochlear electrodes and monitor electrode migration from the cochlea.

BACKGROUND AND OBJECTIVES: The intraosseous subarcuate loop (SL) is a unique variant of the anterior inferior cerebellar artery (AICA), where a loop of the artery is trapped in the petrous bone's subarcuate fossa (SF). Recognizing this variant is crucial for planning cerebellopontine angle (CPA) surgeries; however, data regarding its frequency and management vary in the published literature. A cohort from a single center was studied using MRI to assess its prevalence, and the findings were compared with the existing literature. In addition, an intraoperative guide for mobilizing the intraosseous AICA's SL was provided through a detailed step-by-step cadaveric dissection. METHODS: Two hundred fifty-eight patients who had undergone MRI scans of the CPA (516 sides) were retrospectively reviewed. MRIs displaying vascular loops visible in the axial view were analyzed using multiplanar reconstruction, and the intraosseous loop frequency was evaluated. A scoping review was undertaken to provide an overview of previously published data on its prevalence. One embalmed and latex-injected specimen with intraosseous AICA's SL was dissected through a retrosigmoid approach, and 1 surgical case was detailed, describing the procedure to release it. RESULTS: Intraosseous AICA's SL mobilization involves the identification of its entry and exit points within the petrous bone, dural incision to expose the SF, SF drilling, subarcuate artery division, and detaching the vascular loop. Preservation of a dural cuff is crucial to prevent vascular injury. We analyzed 258 brain MRIs (mean age 55 years, 42% male). The intraosseous AICA's SL was present in 4 of 516 evaluated CPAs (0.8%). The prevalence of the vascular anomaly in the reviewed literature using different radiological modalities ranged from 0.2% to 1.6%. CONCLUSION: The intraosseous AICA's SL is an uncommon anatomic variation detectable by MRI, posing an added risk in CPA surgery. Identifying and properly mobilizing it is crucial for safe vascular preservation.

ObjectiveTo determine which ear environment risk factors impact ossiculoplasty hearing outcomes and to generate a statistically‐valid grading system for ossiculoplasty outcome reporting.Study TypeRetrospective case series.MethodsA multi‐institutional database was generated from cases performed between 2011 and 2019. Preoperative and postoperative hearing thresholds were recorded alongside potential ear environment risk factors. Multiple variable linear regression statistical analyses of risk factors were applied to determine independent association with postoperative pure tone average air‐bone gap (PTA‐ABG). Significant factors were used to generate a statistically‐weighted grading scale of Ear Environment Risk (EER).Results1679 cases had a mean follow‐up time of 33.6 months (SD 36.3) and a mean postoperative PTA‐ABG of 21.2 (SD 12.8). Multiple revision status (p < 0.001), presence of canal wall down mastoidectomy cavity (p = 0.020), absent malleus (p < 0.001), absent stapes superstructure (p = 0.016), frequent otorrhea (p = 0.008), pediatric age (p < 0.001), and blunted/lateralized tympanic membrane (p = 0.003) were independently correlated with PTA‐ABG. These factors were incorporated into an EER Scoring System with four distinct risk groups wherein each risk group was significantly correlated with PTA‐ABG, and this grading system was better correlated with PTA‐ABG (Kendall's τ = 0.193) than other existing published grading scales.ConclusionGrading environment risk according to a novel EER scoring system generates meaningful risk groupings that correlate with ossiculoplasty postoperative PTA‐ABG, and this holds potential to frame reporting of hearing outcomes for future ossiculoplasty research.Level of Evidence3 Laryngoscope, 135:S1–S11, 2025

Objective To evaluate cochlear implant speech perception among patients with sporadic inner ear schwannoma who underwent ipsilateral implantation. Study Design Retrospective multi-institutional cohort study. Setting Eleven tertiary academic medical centers across Germany, Denmark, and the United States. Patients One hundred six patients with sporadic inner ear schwannoma who received an ipsilateral cochlear implant from 2011 to 2022. Interventions Ipsilateral cochlear implantation with observation, stereotactic radiosurgery, or microsurgery for tumor management. Main Outcome Measures Monosyllabic speech perception testing scores and rates of open-set speech perception. Results Among 106 patients studied, 101 (95%) achieved open-set speech perception with a median of 24 months (interquartile range [IQR] 12–42 mo) of audiometric follow-up. Median ipsilateral monosyllabic speech perception testing achieved was 72% (IQR 54–85%), and median ipsilateral AzBio in quiet was 75% (IQR 46–90%). Most (91 of 106 [86%]) underwent microsurgery for tumor control, with cochlear implantation performed simultaneously in 98% (89 of 91) of these patients. The ability to achieve gross total resection significantly differed by tumor complexity, with 97% of low-complexity tumors, 100% of intermediate complexity, and 0% of high-complexity tumors undergoing gross total resection (p < 0.001). However, among patients managed with microsurgery, there was not a statistically significant difference in post-cochlear implantation monosyllabic speech perception scores across complexity groupings, with median scores of 75 and 70% for patients with tumors of low or intermediate complexity and those with tumors of high complexity, respectively (p = 0.5). Eight of 102 patients (8%) assessed experienced deterioration in cochlear implant performance over time. Among the subset of 39 patients with available MRI to review, the region of surveillance interest could be visualized postoperatively on MRI in all cases. Conclusions Open-set speech perception is achieved in most patients with inner ear schwannoma undergoing ipsilateral cochlear implantation. Although cochlear implantation in high-complexity inner ear schwannomas is only possible with incomplete tumor resection, long-term open-set speech perception outcomes are similar to lower-complexity tumors.

Objective To analyze cases of medial migration of vestibular schwannomas to propose an underlying mechanism. Study Design Retrospective chart review. Patients Ten patients from one institution with sporadic vestibular schwannomas that demonstrated medial migration toward the cerebellopontine angle on serial imaging were reviewed. Interventions Among the 10 patients studied, 8 patients underwent stereotactic radiosurgery and 2 were managed with wait-and-scan. All serial imaging was analyzed throughout follow-up. Main Outcome Measures Volumetric and linear measurements were used to assess vestibular schwannoma growth. The fundal fluid cap length was measured from the most lateral end of the neoplasm within the internal auditory canal to the medial end of the cochlea. Pure tone averages of 0.5, 1, 2, and 3 kHz, word recognition scores, and AAO-HNS hearing class were used to assess levels of hearing loss per patient. Results Tumor growth exhibited a positive correlation with medial migration. Of the 10 patients studied, 9 exhibited tumor volume growth from initial to most recent imaging. Median changes in tumor volumes and fundal fluid cap lengths from initial diagnosis to the most recent imaging regardless of intervention were 130 mm3 (range 1,400–2,970) and 2.8 mm (range 1.8–6.0), respectively. Migration was noted in 4 patients prior to any intervention, in 4 patients postradiosurgery, and in 2 patients before and after radiosurgery. Therefore, half of the tumors studied migrated before an intervention and half migrated postradiosurgery. No correlation of migration and hearing decline was observed. Conclusion Medial migration of vestibular schwannoma is associated with an increase in tumor volume, supporting a “tumor squeeze” mechanism within a conical internal auditory canal toward the wider porus acusticus and cerebellopontine angle.

Objective To compare the utility of intraoperative electrically evoked auditory brainstem response (eABR) and electrically evoked stapedial reflex testing (eSRT) for cochlear nerve integrity monitoring during simultaneous translabyrinthine resection of vestibular schwannoma (VS) and cochlear implantation. Study design Historical cohort study. Setting Tertiary academic referral center. Patients Eleven patients (12 cases) who underwent translabyrinthine tumor resection with simultaneous placement of a standard, unmodified cochlear implant (CI). Intervention A CI placed at the beginning of the operation before tumor resection to facilitate intraoperative cochlear nerve monitoring through a CI-delivered electrical stimulus. Main outcome measure Correlation of intraoperative monitoring outcomes with postoperative CI performance. Results Among the 12 cases (median age, 47 years), eABR waveforms were present at the conclusion of tumor resection in 10, including 6 that achieved open set speech perception. Of the 2 cases with negative eABR, 1 achieved open set speech perception. By contrast, of the 8 cases with a positive eSRT response, 7 achieved open set speech perception. Of the 4 cases with a negative eSRT response, none achieved open set speech perception. The 3 cases that did not receive auditory stimulation included 2 with positive and 1 with negative eABR; all 3 had a negative eSRT response. Conclusions Intraoperative eSRT using an unmodified CI is a promising new method for monitoring the integrity of the cochlear nerve during simultaneous VS resection. eSRT response at the conclusion of tumor resection strongly correlated with CI open set speech capacity. Although still useful, eABR was less reliable at predicting postoperative hearing outcomes in this series.