Faculty Bibliography

OBJECTIVES/UNASSIGNED:To better understand the implications of tumor size on auditory brainstem implant (ABI) categories of auditory performance (CAP) score to facilitate more precise patient counselling. DESIGN/UNASSIGNED:Single-center retrospective chart review. SETTING/UNASSIGNED:Tertiary referral center. PARTICIPANTS/UNASSIGNED:Patients > 18 years old with neurofibromatosis type 2 who underwent ABI placement between the years 2009 and 2023 were included. Patients with prior surgical resection were excluded to reduce the potential of previous cochlear nucleus trauma confounding results. MAIN OUTCOME MEASURES/UNASSIGNED:Ipsilateral tumor volume was measured from the preoperative MRI, and the primary endpoint was the 1-year CAP score. RESULTS/UNASSIGNED: = 0.010). CONCLUSION/UNASSIGNED:Increased tumor size has a negative correlation with ultimate ABI performance. There were patients in this study with larger tumor sizes who still benefited from ABI placement. While larger tumor size should not be a contraindication for ABI placement, understanding the role tumor size can have on performance variation can serve to improve tumor management strategies and preoperative counselling.

OBJECTIVE:To evaluate the impact of prolonged unaided duration of deafness (DoD) on speech perception outcomes following cochlear implantation in adults. METHODS:A retrospective review was performed of adult cochlear implant recipients at a single high-volume center between 2012 and 2023. Patients with ≥ 5 years of documented unaided deafness meeting cochlear implant (CI) criteria were stratified into three groups (5-9, 10-19, and ≥ 20 years DoD). The primary outcome was CNC word recognition scores at 3 and 12 months post-operatively. RESULTS:Forty-one patients met inclusion criteria. At 3 months, patients with ≥ 20 years DoD demonstrated lower CNC word recognition scores compared with shorter duration groups. No significant differences were observed between groups at 12 months. Patients without measurable pre-operative hearing thresholds were more likely to be device non-users or fail to achieve open-set speech perception. CONCLUSION/CONCLUSIONS:Patients demonstrated meaningful speech perception outcomes across a range of deafness durations, though longer DoD was associated with slower early improvement. Absence of measurable pre-operative hearing thresholds may identify a subgroup at higher risk for limited functional benefit and should be considered during pre-operative counseling.

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.

OBJECTIVES/UNASSIGNED:To develop and study a novel means of imaging auditory brainstem implant (ABI) paddle placement utilizing postoperative MRI images to determine correlation between ABI performance and ideal paddle placement properties. DESIGN/UNASSIGNED:Single-center retrospective review and image analysis. SETTING/UNASSIGNED:Tertiary referral center. PARTICIPANTS/UNASSIGNED:Patients >18 years old who received an ABI from 2009 to 2023 and had subsequent MRI and auditory performance testing completed. MAIN OUTCOME MEASURES/UNASSIGNED:ABI paddle angulation and insertion depth measure, in addition to categories of auditory performance (CAP) score. RESULTS/UNASSIGNED: = 0.049) once patients with large tumor burden were excluded. Insertion depth and axial angulation showed a negative correlation, in which higher insertion depth was associated with a decrease in axial angulation value, although not statistically significant. CONCLUSION/UNASSIGNED:We present a novel means of measuring ABI paddle placement utilizing MRI to improve the objectivity of paddle placements assessments. Multicenter collaboration to increase the number of patients studied with this new measurement scheme will be required before stronger measurement associations can be determined.

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.

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: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.