Faculty Bibliography

OBJECTIVE:To describe a novel surgical technique utilizing the placement of an apical ground electrode to facilitate intracochlear current modulation in patients with cochlear ossification and incomplete electrode array insertion. PATIENTS/METHODS:Patients with incomplete standard electrode array insertion due to cochlear ossification. INTERVENTION/METHODS:Standard cochlear implant (CI) electrode array insertion, in addition to the placement of the extracochlear ground electrode into the cochlear apex to enable current steering through areas of cochlear ossification and towards the cochlear apex. MAIN OUTCOME MEASURES/METHODS:Procedural safety and patient-reported perceptual differences between programming configurations utilizing the apical ground. RESULTS:Placement of an apical ground electrode was safe and feasible in 3 patients with complex ossified cochlea and was able to augment sound perception, and improve performance, after adjustments to device programming. CONCLUSIONS:Apical ground electrode placement represents a technically achievable adjunct in selected patients with ossified cochlea and incomplete electrode array insertion. This approach may expand the functional stimulation field utilizing intracochlear current modulation to improve patient performance.

OBJECTIVE:To describe intraoperative fluoroscopic and transimpedance matrix (TIM) findings during cochlear implantation in a patient with bilateral cochlear malformations, highlighting the dynamic relationship between electrode position and evolving TIM heatmap patterns. STUDY DESIGN/METHODS:Case report. METHODS:Retrospective review of patient medical and radiographic records, intraoperative fluoroscopy, and TIM data. RESULTS:Initial insertion produced a previously characterized TIM skip heat pattern seen in patients with incomplete partition type II and deficient interscalar septal width. This prompted partial electrode withdrawal under fluoroscopy, which subsequently resulted in a TIM central heat pattern, representing a symmetric voltage concentration around the mid-array region. Advancing the array slightly resulted in a skip heat pattern with a more defined current delineation and a more favorable x-ray profile. Interestingly, SmartNav analysis interpreted the TIM data as a tip fold over, despite good positioning. CONCLUSION/CONCLUSIONS:This case visually demonstrates which small positional changes of electrodes within malformed cochleae can transform TIM morphology, helping to elucidate why certain patterns occur, and the next steps to study clinical relevance.

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.

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: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.

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.

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.

The current management of vestibular schwannomas (VS) includes observation, microsurgery, and stereotactic radiosurgery (SRS) or radiotherapy. Both microsurgery (MS) and irradiation have the potential for treatment failures. For microsurgical failures, options include observation, revision surgery, and SRS. SRS is most commonly used, as it carries a low risk of adverse events. Salvage MS following previous MS is reserved for specific cases and is often surgically challenging. For radiosurgical failures, both salvage MS and repeat SRS may be used. Salvage MS following SRS also tends to be challenging, although excellent facial nerve outcomes are achievable. Furthermore, repeat SRS is an emerging concept and should be considered in small tumors that are growing but are asymptomatic. This chapter is aimed at reviewing an approach to failure of primary interventions for vestibular schwannomas, with an emphasis on the time interval between modalities, tumor control rates, functional outcomes, and complications.