Faculty Bibliography

OBJECTIVE:We sought to apply a previously developed transimpedance (TIM) heatmap pattern classification scheme in patients with no known risk factors for cochlear anomalies, in addition to patients implanted in the revision setting, to better understand the incidence of pattern variants, and potential clinical implications. STUDY DESIGN/METHODS:Single-center retrospective review. SETTING/METHODS:Tertiary referral centre. PATIENTS/METHODS:Patients older than 6 months of age who underwent cochlear implantation between June 2020 and June 2024 with normal gross cochlear anatomy and no concern for fibrosis that had intraoperative TIM testing completed. Patients undergoing revision implantation were also included as a separate cohort. INTERVENTION/METHODS:None. MAIN OUTCOME MEASURES/METHODS:The number of patients with normal and variant TIM patterns was evaluated for each cohort. TIM patterns were subsequently compared with the electrode position found on intraoperative x-ray. RESULTS:There were 321 ears that underwent implantation and subsequent intraoperative TIM assessment meeting inclusion criteria. Of these, 310 (96.6%) were in the primary surgery setting, and 11 (3.4%) were in the revision surgical setting. In the primary surgical setting, 86.4% (n=268) of the implants demonstrated a normal TIM heatmap. Compared with the primary surgical setting, where only 45.5% (n=5) of revision surgery TIM heatmaps were interpreted as normal. One patient in the revision setting had a newly identified "double X" pattern corresponding to a normal electrode position on x-ray. CONCLUSIONS:There is a decreased incidence of previously developed TIM heatmap pattern variants in CI recipients with normal gross cochlear anatomy.

OBJECTIVE:NF2-related schwannomatosis (NF2-SWN) is an autosomal dominant genetic disorder characterized by the development of schwannomas, meningiomas, and spinal ependymomas. Treatment with bevacizumab, a monoclonal antibody against VEGF, has been shown to result in decreased vestibular schwannoma size and hearing improvement in ~50% of NF2-SWN patients. It is unknown whether the same degree of benefit is seen in younger patients compared with older patients. The objective of this study is to determine the association between age and bevacizumab treatment outcomes in NF2-SWN. STUDY DESIGN/METHODS:Retrospective cohort study. SETTING/METHODS:Tertiary referral center. PATIENTS/METHODS:Thirty-seven patients with NF2-SWN. INTERVENTIONS/METHODS:Bevacizumab. MAIN OUTCOME MEASURES/METHODS:Change in tumor size of 20% or more. RESULTS:This study includes 37 patients with NF2-SWN who were treated with bevacizumab at our institution between 2014 and 2024. They were divided into 2 groups: 22 adults over the age of 25 (26 to 71 y) and 15 adolescent and young adult (AYA) patients under the age of 25 (12 to 24 y). The median treatment duration was 2.1 years. A significantly higher proportion of AYA schwannomas (37.5%, n=9) exhibited radiographic tumor progression during the treatment period compared with those of the older patient group (11.9%, n=5) (P=0.026), despite similar pre-treatment growth rates. There was no significant difference in the proportion of older and younger patients with hearing decline, improvement, or stability (P>0.05). CONCLUSIONS:AYA patients were significantly more likely to exhibit progression of tumor growth during bevacizumab treatment compared with older patients, though no significant differences were detected in hearing outcomes.

OBJECTIVE:To characterize patient outcomes after primary stereotactic radiosurgery (SRS) for the management of sporadic facial nerve schwannoma. STUDY DESIGN/METHODS:Retrospective cohort study. SETTING/METHODS:Six tertiary referral centers across the United States and United Kingdom. PATIENTS/METHODS:Adults undergoing SRS from 2000 through 2023 for sporadic facial nerve schwannoma along any segment of the facial nerve were included. Patients with NF2-related schwannomatosis were excluded. INTERVENTION/METHODS:Stereotactic radiosurgery. MAIN OUTCOME MEASURE/METHODS:Long-term tumor control. RESULTS:Among 60 patients meeting inclusion, the median age at SRS was 52 years (IQR: 41 to 64) with a median tumor size of 19.5 mm (IQR: 14.7 to 22.8). Tumors commonly involved the internal auditory canal (73%), cisternal (49%), geniculate/labyrinthine (47%), and tympanic segments (22%). Two patients experienced SRS failure and underwent salvage treatment; salvage-free survival rates (95% CI; number still at risk) at 1, 3, 5, and 10 years after SRS were 100% (100 to 100; 55), 100% (100 to 100; 36), 100% (100 to 100; 18), and 87% (72 to 100; 9), respectively. Among 31 (52%) patients with House-Brackmann (HB) grade I facial function at presentation, only 6 demonstrated worse facial function at a median of 3.2 years (IQR: 1.7 to 6.6) after SRS. Of 18 patients with serviceable hearing (AAO-HNS class A/B) at SRS, 13 maintained serviceable hearing at a median of 1.0 years (IQR: 0.5 to 4.9) of post-SRS audiometric follow-up. CONCLUSIONS:Durable tumor control after primary SRS for sporadic facial nerve schwannoma is achieved in most patients. Among those with HB grade I facial function at presentation, treatment with SRS harbors limited additional risk of facial paresis beyond observation alone.

UNLABELLED:<p>Introduction: Cochlear implantation has demonstrated benefit for restoring hearing in patients with Ménière's disease. We sought to examine disease and management factors that may influence postoperative speech performance and vertigo control. METHODS:A single-center retrospective chart review between 2010 and 2023 of patients with Ménière's disease receiving a cochlear implant (CI). The primary outcome was 1-year postoperative word recognition score on Consonant-Nucleus-Consonant (CNC) testing. Postoperative vertigo control was assessed as a secondary outcome. Variables including concurrent labyrinthectomy, pre- and postoperative Ménière's disease symptoms and treatments, duration of deafness, and hearing loss laterality were analyzed. RESULTS:Twenty-five patients were identified over the study period. Of those, 9 (36%) also underwent labyrinthectomy; 6 (67%) were performed simultaneously with CI and 3 (33%) received a CI following surgical ablation. There was a statistically significant (p = 0.03) higher rate of bilateral Ménière's disease in the CI-only cohort (n = 9, 56%), compared to the cochlear implant and labyrinthectomy (CI + L) cohort (n = 1, 11%). There was also a higher rate of preoperative uncontrolled vertigo (n = 5, 56%) in the CI + L cohort compared to the CI-only cohort (n = 3, 20%), although this did not reach statistical significance (p = 0.08). The average pre- and postoperative CNC score for the CI + L cohort was 3.6 (SD 5.9) and 36.7 (SD 17.5), respectively, and 7.1 (SD 10.1) and 62.1 (SD 14.3) for the CI-only group. There was a statistically significant difference noted at most recent CNC follow-up testing (p = 0.01) between the CI + L and CI-only group. CONCLUSION/CONCLUSIONS:Patients with Ménière's disease meeting CI candidacy criteria may undergo CI safely and achieve speech performance benefit. A trend toward worse performance in patients who undergo concurrent labyrinthectomy with CI compared to CI alone was seen which warrants further study. </p>.

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.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Surgery in NF2-related schwannomatosis (NF2-SWN) vestibular schwannoma (VS) carries a higher risk of facial nerve damage, hearing loss, and partial resection, than in sporadic cases. Radiosurgery is also associated with higher failure compared with sporadic schwannomas. Nowadays, bevacizumab (BEV) is frequently considered in the NF2-SWN population. However, some patients experience progression despite treatment. Among other surgical risks, in BEV-treated patients, hemorrhage and impaired healing are specific considerations. These concerns have led manufacturers to recommend stopping BEV 6 to 8 weeks preoperatively. The aim of our multicentric study was to assess the perioperative bleeding risk and postoperative outcomes in NF2-SWN patients undergoing VS surgery after preoperative BEV treatment. METHODS:Our retrospective analysis included medical and surgical records along with imaging reviews from 4 high-volume tertiary academic referral centers for NF2-SWN and VS. RESULTS:A total of 21 patients met the inclusion criteria. VS had a mean volume of 13.2 ±7.6 cm3 corresponding to 1 KOOS III and 20 KOOS IV. BEV was stopped at a mean of 5.8 ± 4.0 months before surgery with a total mean treatment duration of 33.7 ± 20.7 months and a monthly dose of 10.2 ± 4.1 mg/kg. Intraoperatively, the tumor was assessed to be bloody by the operating surgeons in 7 patients. Late BEV discontinuation and high cumulative dose independently predicted perioperative bleeding and longer surgery duration. No other complication such as wound dehiscence was reported. CONCLUSION/CONCLUSIONS:Our findings suggest that a higher cumulative BEV dose (∼600 mg/kg) and a longer interval between BEV discontinuation and surgery (∼8 months) are associated with a modest but statistically significant increase in intraoperative bleeding risk. Based on these observations, a BEV-free window between 6 weeks and 6 months (depending on the clinical scenario) before tumor resection seems optimal, particularly for patients with high cumulative exposure.

Congenital cholesteatomas are defined as a collection of epithelium in the absence of prior surgery or pathologic retraction. They are most commonly found in the middle ear and are thought to arise from a residual epithelial rest present since birth; however, a small number of cases present with disease isolated to the mastoid bone. One such case and a review of prior reports are presented. A 29-year-old male with a 2-year history of headaches and no otologic surgery was found to have a destructive mass centered in the right mastoid bone, invading the jugular foramen and posterior fossa without middle ear disease. He underwent a mastoidectomy with complete resection of the cholesteatoma. A literature review identified 21 prior cases of isolated mastoid congenital cholesteatoma. Congenital cholesteatoma should be considered in the differential diagnosis when patients present with postauricular pain or headaches. Mastoidectomy is considered the treatment of choice.

OBJECTIVES/OBJECTIVE:Real-time monitoring of cochlear function to predict the loss of residual hearing after cochlear implantation is now possible. Current approaches monitor the cochlear microphonic (CM) during implantation from the electrode at the tip of the implant. A drop in CM response of >30% is associated with poorer hearing outcomes. However, there is prior evidence that CM amplitude can fluctuate in a manner unrelated to hearing trauma, leading to false positives. By monitoring another cochlear response, the auditory nerve neurophonic (ANN), a differentiation between CM drops that result in reduced cochlear output from false positives may be possible. The hypothesis tested in the present work was that ANN/CM ratios measured during a CM drop will increase during drops not associated with postoperative hearing loss. DESIGN/METHODS:Twenty-eight adult participants with known CM drops during implantation were taken from a larger data set. This contains adult cochlear implant candidates scheduled to receive a Cochlear Nucleus cochlear implant with either the slim-straight or slim-modiolar electrode array with preoperative audiometric low-frequency average thresholds of ≤80 dB HL at 500, 750, and 1000 Hz in the ear to be implanted. Patients were recruited from eight international implant sites. Pure-tone audiometry was measured postoperatively and 4 to 6 weeks after implantation. Electrocochleography was measured during and immediately after the implantation of the array in response to a 500-Hz, 6-msec pure-tone pip at 110 dB HL. RESULTS:The ANN/CM ratio rose during CM drops in 19 of these patients and decreased in 9. At the follow-up timepoint, patients with a decreasing ANN/CM ratio had a median hearing loss of 29.0 dB, significantly worse than the group with increasing ratio at 13.3 dB ( p = 0.004). Considering only the change in ANN amplitude during a CM drop led to smaller groups (ANN drop during CM drop N = 17, ANN increasing during CM drop N = 6) due to 5 patients having undetectable ANN during the CM drop. Using the ANN alone also led to as poorer prediction of hearing preservation, with median hearing preservation in the ANN increasing group of 12.9 dB, significantly better than the ANN decreasing group of 25 dB ( p = 0.02). The group with a decreasing ANN/CM ratio had maximum CM amplitude immediately after insertion lower than the maximum amplitude reached during insertion (mean maximum postinsertion amplitude of 98% of during-insertion amplitude). In comparison, the ANN/CM ratio increasing group tended to have a larger CM amplitude immediately after insertion (mean maximum CM amplitude postinsertion of 164% of the maximum during-insertion amplitude). CONCLUSIONS:These data show that the ANN/CM ratio is a measure that can differentiate between patients with CM drops that lead to a loss of residual hearing and those that do not. The ANN/CM ratio is easily measured and responds rapidly during a CM drop, showing clinical promise for improving current and developing approaches to intraoperative monitoring.

OBJECTIVE:Limited 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 DESIGN/METHODS:A historical cohort study. SETTING/METHODS:Seven centers across the United States and Norway. METHODS:Adults 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. RESULTS:Among 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). CONCLUSION/CONCLUSIONS:Corroborated 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.