Faculty Bibliography

Auditory brainstem implants (ABIs) stimulate the auditory system at the cochlear nucleus, bypassing the peripheral auditory system including the auditory nerve. They are used in patients who are not cochlear implant candidates. Current criteria for use in the United States are neurofibromatosis type 2 patients 12 years or older undergoing first- or second-side vestibular schwannoma removal. However, there are other nontumor conditions in which patients may benefit from an ABI, such as bilateral cochlear nerve aplasia and severe cochlear malformation not amendable to cochlear implantation. Recent experience with ABI in the pediatric population demonstrates good safety profile and encouraging results.

Objective: To describe cochlear implantation (CI) outcomes for rehabilitation of hearing loss due to retrocochlear pathology and/or its treatment.
Method(s): Retrospective review between 1995 and 2019 from a single tertiary care center of all patients with retrocochlear pathology who underwent CI. Demographics, clinical history, and audiometric data were reviewed. Study endpoints include (1) logged device use, (2) ability to achieve auditory perception, and (3) word recognition score (WRS) in the CI-only condition.
Result(s): Thirty-two patients (63% of females) with retrocochlear pathology were implanted at our center. The average age at implantation was 46.9 years (SD: 19, range: 13-80). Mean duration of deafness was 4.5 years (SD: 5.0, range: 0.4-19.0). Etiology of hearing loss included VS in 24 (75%), CNS malignancy treated with radiation in 4 (13%), intralabyrinthine schwannoma in 2 (6%), head and neck malignancy treated with radiation in 1 (3%), and superficial siderosis in 1 (3%). The mean preoperative PTA was 95.8 dBHL (SD 24.7) and WRS was 7.2% (SD 13.1). Of the 24 VSs, 21 were NF2-associated and 3 were sporadic. The mean tumor size was 1.64 cm (SD: 0.6, range: 0.5-2.6 cm). At the time of CI, 11 patients had prior microsurgery, 6 patients had prior radiation to the ipsilateral tumor, and 7 patients had stable tumors without prior surgery or radiation. Device use was classified as regular (>7 hours/day) in 15 (47%), limited (<7 hours/day) in 12 (38%), and nonuse is 5 (16%). The audiometric outcomes of 26 patients are reported, as the other 6 patients have been implanted too recently for review. Auditory perception was achieved in 24/26 patients. The two patients who failed to achieve auditory perception underwent prior surgery. Open-set speech recognition (WRS > 20%) was achieved in 18 patients. Meaningful sound perception but without significant open-set speech (WRS < 20%) was seen in six patients. Altogether, the mean WRS at most recent follow-up (mean: 3.4 years, SD: 1.8) for the observation, microsurgery, and radiation cohorts was 51% (SD: 15), 36% (SD: 28), and 39% (SD: 26), respectively. Over long-term follow-up, two patients experienced decline in CI performance associated with tumor regrowth and necessitated additional surgery; both underwent explantation of the CI and successful auditory brainstem implantation. The remaining patients have demonstrated durable benefit. A multivariate analysis is presented to evaluate the effects of the following variables: duration of deafness, time interval between treatment and CI, diagnosis of NF2, treatment cohort, pathology, and status of hearing in the contralateral ear.
Conclusion(s): In appropriately selected patients, cochlear implantation is feasible for the rehabilitation of hearing loss due to retrocochlear pathology and/or its treatment. Given the heterogeneity inherent to this population, outcomes are variable. In most cases, auditory percept was achieved and over half of the patients obtained open-set speech perception, irrespective of prior management and treatment

OBJECTIVE:We conducted a quality improvement project to increase the rate of discharges before noon (DBN) in the otolaryngology department at a tertiary care center. METHODS:Based on a Plan-Do-Study-Act framework, monthly discharge data and observed-to-expected (O:E) length of stay were collected and shared with the department members monthly. A target of 43% DBN was predetermined by the center (Plan). The following interventions were implemented (Do): discharge planning starting at the time of admission, focus on early attending-to-resident team communication, placement of discharge order prior to rounding, and weekly reminders to the entire department. RESULTS:Discharges were monitored for 3 years. For the year prior to this study, a minority of patients were discharged before noon (12 months: 75 of 190, 36%). During the first 6 months of monitoring (Study), no significant improvement was identified (34 of 95, 36%). After interventions, performance significantly improved (31 months: 250 of 548, 68%). The performance was consistently above the predetermined target of 43%. During the study time, O:E length of stay remained below the predetermined target (O:E ratio, 0.90; hospital target, 0.93). DISCUSSION/CONCLUSIONS:Comprehensive discharge planning beginning at the time of admission, weekly reminders, and improved communication (Act) can help to prioritize DBN and increase the percentage of discharges before noon. IMPLICATIONS FOR PRACTICE/CONCLUSIONS:By utilizing a quality improvement framework, significant improvements in timely discharge can be achieved and sustained with changes in workflow and departmental culture. These changes can be achieved without increases in resources or prolonging the length of stay.

As the world's geriatric population continues to grow at an unprecedented rate, an increasing number of elderly patients are seeking hearing rehabilitation strategies, including cochlear implantation (CI). However, CI surgery in elderly patients has been met with trepidation given fears of physical and cognitive complications associated with general anesthesia. Cochlear implant surgery under local anesthesia with conscious sedation (LA-CS) in the elderly population is a safe and feasible alternative to general anesthesia. Elderly patients who are too infirm for general anesthesia or who choose not to pursue CI due to fears of the cognitive or medical consequences of general anesthesia should be counseled on the option of doing it under LA-CS by experienced CI surgeons. This article provides an overview of the surgical technique and technical nuances of performing CI surgery under LA-CS.

OBJECTIVE:The goal of this study was to describe the clinical presentation associated with atypical schwannoma of the cerebellopontine angle, characterize the pathologic findings and describe the long-term outcome. MATERIALS AND METHODS/METHODS:The study design was retrospective case review of patients with the histopathologic diagnosis of atypical and benign schwannoma of the cerebellopontine angle diagnosed at the study institution over a 10-year period. SETTING/METHODS:Tertiary referral center. MAIN OUTCOMES MEASURE/METHODS:Demographic data of the cohort were recorded. Findings on pathology were evaluated. Initial treatment and post-operative course was recorded. Main outcome measures were clinical presentation, including cranial nerve deficits at the time of presentation, complication and recurrence rates. RESULTS:At presentation, a somewhat accelerated course of cranial nerve deficit was noted among patients with atypical schwannoma as compared to benign schwannoma. In the immediate post-operative period, there were no differences noted in the complication rate. Atypical schwannomas appear to have higher recurrence rate compared to benign schwannomas. CONCLUSIONS:Atypical schwannoma is an intermediate disease process with an accelerated clinical course and higher recurrence rate as compared to vestibular schwannoma. Traditional operative approaches may be employed without increased concern for post-operative complications. Thorough counseling and close follow-up should be offered to these patients given the higher recurrence rate. Larger studies are required to determine if these patients need more frequent MRIs for long-term surveillance.

BACKGROUND:Intraosseous petrous apex schwannomas are an exceedingly rare entity; little is known about their epidemiology, natural history, and post-operative outcomes. CASE DESCRIPTION/METHODS:Here, we present the fourth known case of a primary intraosseous schwannoma of the petrous apex: a 68-year-old woman presenting with diplopia, facial numbness, progressive intermittent vertigo, tinnitus, diminished hearing, and ataxia. She underwent a transtemporal approach for subtotal resection of the tumor with subsequent stereotactic radiosurgery. CONCLUSIONS:Our two-year follow-up demonstrates slow growth and success of multimodal management in the treatment of these tumors. We review the three prior reports of petrous apex schwannomas, and identify unifying radiographic and clinical characteristics in order to aid in future diagnostic considerations of lesions of the petrous apex.

OBJECTIVE:There remains a large discrepancy among surgeons in expectations of vestibular schwannoma (VS) growth. The anticipated growth rate of a VS and its potential clinical impact are important factors when deciding whether to observe the lesion over time or to intervene. Previous studies of VS natural growth remain limited, mostly confined to linear measurements, often without high-resolution, thin-sequence imaging. The present study comprehensively assessed natural tumor growth rates using volumetric measurements. METHODS:Between 2012 and 2018, 212 treatment-naïve patients diagnosed with a unilateral VS were evaluated. A total of 699 MR images were assessed, with a range of 2-11 MR images per patient. All MR images preceded any intervention, with patients subsequently being observed through completion of data analysis (36%) or treated with stereotactic radiosurgery (32%) or microsurgical resection (32%). To determine precise tumor volumes, the tumor area was outlined on every slice, and the products of the area and slice thickness were summed (99% of scans were ≤ 1-mm slice thickness). A multilevel model with random effects was used to assess the mean volume change over time. Each tumor was categorized as one of the following: growing (volume increase by more than 20% per year), fast growing (volume increase by more than 100% per year), stable (volume change between 20% decrease and 20% increase per year), and shrinking (volume decrease by more than 20% per year). RESULTS:The mean VS volumetric growth rate was 33.5% per year (95% CI 26.9%-40.5%, p < 0.001). When assessing the frequencies of individual tumor annual growth rates, 66% demonstrated growth (30% fast growing), 33% were stable, and 1% exhibited shrinking over an average interval of 25 months. Larger tumors were associated with increased absolute growth, but there was no relationship between tumor size and proportional growth rate. There was also no relationship between patient age and tumor growth rate. CONCLUSIONS:This study comprehensively assessed VS volumetric growth rates using high-resolution images and was conducted in a large and diverse patient sample. The majority of the tumors exhibited growth, with about one-third growing at a rate of 100% per year. These findings may contribute to a consensus understanding of tumor behavior and inform clinical decisions regarding whether to intervene or observe.

An auditory brainstem implant (ABI) is a surgically implanted central neural auditory prosthesis for the treatment of profound sensorineural hearing loss in children and adults who are not cochlear implant candidates due to a lack of anatomically intact cochlear nerves or implantable cochleae. The device consists of a multielectrode surface array which is placed within the lateral recess of the fourth ventricle along the brainstem and directly stimulates the cochlear nucleus, thereby bypassing the peripheral auditory system. In the United States, candidacy criteria for ABI include deaf patients with neurofibromatosis type 2 (NF2) who are 12 years or older undergoing first- or second-side vestibular schwannoma resection. In recent years, several non-NF2 indications for ABI have been explored, including bilateral cochlear nerve avulsion from trauma, complete ossification of the cochlea due to meningitis, or a severe cochlear malformation not amenable to cochlear implantation. In addition, growing experience with ABI in infants and children has been documented with encouraging outcomes. While cochlear implantation generally remains the first-line option for hearing rehabilitation in NF2 patients with stable tumors or post hearing preservation surgery where hearing is lost but a cochlear nerve remains accessible for stimulation, an ABI is the next alternative in cases where the cochlear nerve is absent and/or if the cochlea cannot be implanted. Herein, we review ABI device design, clinical evaluation, indications, operative technique, and outcomes as it relates to lateral skull base pathology.