Modern Hearing Preservation Outcomes After Vestibular Schwannoma Stereotactic Radiosurgery
BACKGROUND:For patients with vestibular schwannoma (VS), stereotactic radiosurgery (SRS) has proven effective in controlling tumor growth while hearing preservation remains a key goal. OBJECTIVE:To evaluate hearing outcomes in the modern era of cochlear dose restriction. METHODS:During the years 2013 to 2018, 353 patients underwent Gamma knife surgery for VS at our institution. We followed 175 patients with pre-SRS serviceable hearing (Gardner-Robertson Score, GR 1 and 2). Volumetric and dosimetry data were collected, including biological effective dose, integral doses of total and intracanalicular tumor components, and hearing outcomes. RESULTS:The mean age was 56 years, 74 patients (42%) had a baseline GR of 2, and the mean cochlear dose was 3.5 Gy. The time to serviceable hearing loss (GR 3-4) was 38 months (95% CI 26-46), with 77% and 62% hearing preservation in the first and second years, respectively. Patients optimal for best hearing outcomes were younger than 58 years with a baseline GR of 1, free canal space â‰¥0.041 cc (diameter of 4.5 mm), and mean cochlear dose <3.1 Gy. For such patients, hearing preservation rates were 92% by 12 months and 81% by 2 years, staying stable for >5 years post-SRS, significantly higher than the rest of the population. CONCLUSION/CONCLUSIONS:Hearing preservation after SRS for patients with VS with serviceable hearing is correlated to the specific baseline GR score (1 or 2), age, cochlear dose, and biological effective dose. Increased tumor-free canal space correlates with better outcomes. The most durable hearing preservation correlates with factors commonly associated with smaller tumors away from the cochlea.
Cochlear Implant Outcomes in CHARGE Syndrome: Updated Perspectives
OBJECTIVE:To evaluate outcomes of auditory implants in children with CHARGE syndrome and describe the evolution in management of hearing loss in this complex population. METHODS:A retrospective case review was performed at a tertiary referral center. Children with CHARGE syndrome who received either a cochlear implant (CI) or auditory brainstem implant (ABI) were included. Clinical records, demographic information, CHARGE features, neuroimaging, audiology, hearing rehabilitation interventions, operative notes, and outcomes were reviewed. RESULTS:Thirteen children with CHARGE syndrome underwent a total of 19 cochlear implants between 2008 and 2020. Among the congenitally deafened children (nâ€Š=â€Š9), six underwent bilateral implantation (five simultaneous and one sequential). Bilateral implantation was performed even in the presence of diminutive-appearing cochlear nerves. The average age of implantation was 1.1â€Šyears, and the mean device use time was 9.4â€Šhours per day. Patients showed improvements in subjective family assessment related to hearing. In this group, two patients use oral communication, five use total communication, and two use sign language exclusively. Among the children with progressive hearing loss, the mean age of hearing deterioration was 4.4â€Šyears of age, and the device use time on average was 9.8â€Šhours per day. The highest performer in the cohort was a child who lost hearing in their only hearing ear at age 4 and had normal cochleovestibular anatomy on that side. One child received an auditory brainstem implant at age two after deriving no benefit from a CI and can detect environmental sounds but is currently a nonuser. Over time, we noted that implantation occurred earlier in life and that practice has shifted toward bilateral implantation. CONCLUSIONS:Compared to a previous institutional cohort, children evaluated in this study were often implanted at a younger age and bilaterally with significantly improved outcomes. A CI evaluation should be considered in children with CHARGE syndrome to maximize sensory input and auditory ability.
Stimulating the Cochlear Apex Without Longer Electrodes: Preliminary Results With a New Approach
OBJECTIVE:To investigate a new surgical and signal processing technique that provides apical stimulation of the cochlea using a cochlear implant without extending the length of the electrode array. PATIENTS/METHODS:Three adult patients who underwent cochlear implantation using this new technique. INTERVENTIONS/METHODS:The patients received a cochlear implant. The surgery differed from the standard approach in that a ground electrode was placed in the cochlear helicotrema via an apical cochleostomy rather than in its typical location underneath the temporalis muscle. Clinical fitting was modified such that low frequencies were represented using the apically placed electrode as a ground. MAIN OUTCOME MEASURES/METHODS:Pitch scaling and speech recognition. RESULTS:All surgeries were successful with no complications. Pitch scaling demonstrated that use of the apically placed electrode as a ground lowered the perceived pitch of electric stimulation relative to monopolar stimulation. Speech understanding was improved compared with preoperative scores. CONCLUSIONS:The new surgical approach and clinical fitting are feasible. A lower pitch is perceived when using the apically placed electrode as a ground relative to stimulation using an extracochlear ground (i.e., monopolar mode), suggesting that stimulation can be provided more apically without the use of a longer electrode array. Further work is required to determine potential improvements in outcomes and optimal signal processing for the new approach.
Outcomes of Salvage Resection and Radiosurgery Following Failed Primary Treatment of Vestibular Schwannomas
OBJECTIVE:To evaluate outcomes following salvage microsurgery (MS) and salvage stereotactic radiosurgery (SRS) after failure of primary treatment for vestibular schwannomas (VS). STUDY DESIGN/METHODS:Retrospective chart review. SETTING/METHODS:Tertiary referral center. METHODS:Patients with more than 1 intervention for their VS were divided into 4 groups: MS followed by SRS (n = 61), MS followed by MS (n = 9), SRS followed by MS (n = 7), and SRS followed by SRS (n = 7), and outcomes were evaluated. RESULTS:A total of 77 patients were included (84 procedures). In group 1 (MS then SRS), 3% developed a decline in facial function, 3% developed trigeminal sensory loss, and 13% patients had gradual improvement of facial nerve function following SRS. Group 2 (MS then MS) had the highest rates of facial nerve deterioration, although all but 1 patient achieved a House-Brackmann score of II or III. Gross-total resection (GTR) was achieved in 56% of patients. When a different approach was used for salvage resection, GTR occurred more commonly, and facial nerve outcomes were similar. In group 3 (SRS then MS), GTR occurred in 43% of cases, and 2 of 7 patients developed worsened facial function. In group 4 (SRS then SRS), no patient developed facial weakness after reirradiation, and 1 developed a trigeminal nerve deficit. CONCLUSIONS:For MS recurrences/residuals, SRS is the mainstay of treatment and does not preclude facial function recovery. If salvage microsurgery is required, an alternate approach should be considered. For SRS failures, when MS is required, less-than GTR may be preferable, and reirradiation is a potential safe alternative.
Hearing loss and volumetric growth rate in untreated vestibular schwannoma
OBJECTIVE:In this study, the authors aimed to clarify the relationship between hearing loss and tumor volumetric growth rates in patients with untreated vestibular schwannoma (VS). METHODS:Records of 128 treatment-naive patients diagnosed with unilateral VS between 2012 and 2018 with serial audiometric assessment and MRI were reviewed. Tumor growth rates were determined from initial and final tumor volumes, with a median follow-up of 24.3 months (IQR 8.5-48.8 months). Hearing changes were based on pure tone averages, speech discrimination scores, and American Academy of Otolaryngology-Head and Neck Surgery hearing class. Primary outcomes were the loss of class A hearing and loss of serviceable hearing, estimated using the Kaplan-Meier method and with associations estimated from Cox proportional hazards models and reported as hazard ratios. RESULTS:Larger initial tumor size was associated with an increased risk of losing class A (HR 1.5 for a 1-cm3 increase; p = 0.047) and serviceable (HR 1.3; p < 0.001) hearing. Additionally, increasing volumetric tumor growth rate was associated with elevated risk of loss of class A hearing (HR 1.2 for increase of 100% per year; p = 0.031) and serviceable hearing (HR 1.2; p = 0.014). Hazard ratios increased linearly with increasing growth rates, without any evident threshold growth rate that resulted in a large, sudden increased risk of hearing loss. CONCLUSIONS:Larger initial tumor size and faster tumor growth rates were associated with an elevated risk of loss of class A and serviceable hearing.
Cochlear Implant Outcomes in Neurofibromatosis Type 2: Implications for Management
OBJECTIVE:To describe our institutional experience with cochlear implantation (CI) for rehabilitation of hearing loss in Neurofibromatosis type 2 (NF2) patients. STUDY DESIGN/METHODS:Retrospective review between 1989 and 2019. SETTING/METHODS:Tertiary-care center. PATIENTS/METHODS:Twenty-four patients (67% female, mean age 45.6years) with NF2. Management of their ipsilateral vestibular schwannoma included microsurgery (n=12), stereotactic radiation (n=5), and observation (n=7). INTERVENTIONS/METHODS:Cochlear implantation. MAIN OUTCOME MEASURES/METHODS:Ability to obtain open-set speech, daily device usage and long-term device benefit. RESULTS:All patients achieved some degree of sound awareness with CI. Nineteen patients (79%) achieved open-set speech understanding with a mean word-recognition score of 43% (range 0-88%). Patients with tumors 1.5 cm or less demonstrated the better speech understanding, without significant differences among treatment modalities. For tumors greater than 1.5 cm, patients who underwent microsurgery had a lower rate of open-set speech understanding compared to those treated with radiation or observation. Regular daily device use in 83% of patients was found. Long-term use (>10years) was observed in several patients, though some ultimately required reimplantation with an auditory brainstem implant due to progressive tumor growth. Mean follow-up duration was 4.1 years (range 0.4-15). CONCLUSIONS:Cochlear implantation can be an effective treatment for hearing loss in NF2 patients provided the cochlear nerve is intact, regardless of prior management for the ipsilateral tumor. The degree of benefit varies and is influenced by tumor size. Management strategies that preserve the cochlear nerve maximize the interval during which a CI could be of benefit to NF2 patients.
Cochlear Implantation in Sporadic Vestibular Schwannoma and Other Retrocochlear Pathology: A Case Series
OBJECTIVE:To describe outcomes with cochlear implantation (CI) for rehabilitation of hearing loss in patients with sporadic vestibular schwannomas (VS) and other retrocochlear pathologies. STUDY DESIGN/METHODS:Retrospective review. SETTING/METHODS:Tertiary-care center. PATIENTS/METHODS:Twenty three cases in 19 patients (53% men, mean age 55.8 yr) with non-neurofibromatosis type 2 related retrocochlear pathology. INTERVENTIONS/METHODS:Unilateral or bilateral CI. MAIN OUTCOME MEASURES/METHODS:Word recognition score, device usage. RESULTS:Etiology of deafness included sporadic VS (nâ€Š=â€Š9, 39%), radiation after head and neck or central nervous system (CNS) malignancy (nâ€Š=â€Š8, 35%), superficial siderosis (nâ€Š=â€Š3, 13%), neurosarcoidosis (nâ€Š=â€Š2, 9%), and pontine stroke (nâ€Š=â€Š1, 4%). Mean follow-up duration was 2.3 years (standard deviation [SD] 3.0; range, 0.2-9.4). Auditory perception was achieved in 20 out of 22 patients (91%) who have been activated. Mean WRS in patients with sporadic VS was 18% (SD 20; range, 0-44). Mean WRS in patients with non-VS retrocochlear pathology was 55% (SD 30; range, 0-94). Data logs showed 7.0â€Šh/d of average use (SD 4.3; range, 0-13). CONCLUSIONS:Appropriately selected patients with retrocochlear pathology may benefit from CI so long as the patient has a cochlear fluid signal and an intact cochlear nerve. Patients with sporadic VS patients and normal contralateral hearing exhibited guarded outcomes with CI, whereas most patients with non-VS retrocochlear pathologies demonstrated open-set speech understanding scores comparable to or slightly worse than conventional CI candidates. Since variable performance benefit is observed with CI in patients with retrocochlear pathology, counseling is imperative to align patient expectations with realistic outcomes.
Skull Base Aerosol Generating Cases Amidst the COVID-19 Pandemic: An Experience from the Epicenter
Soon after the World Health Organization declared the severe acute respiratory syndrome coronavirus 2 a global health emergency on January 30, 2020, New York City was plagued by the virus and its health system and economy pushed to their limits. The majority of the limited neurosurgical data in relation to COVID-19 is anecdotal and the higher theoretical risk of transmission of the virus among skull base aerosol generating (SBAG) cases has not been investigated or discussed in a neurosurgical population. We discuss a series of 13 patients who underwent 15 SBAG surgical procedures during the peak of COVID-19 in our hospital system and the protocols use perioperatively for their procedures. Our data support that with proper preoperative testing, a well-delineated surgical algorithm, and appropriate personal protective equipment, emergent/urgent cases can be done safely in hospitals that are currently experiencing high volumes of COVID-19 cases as we did in March to May of 2020.
From Bimodal Hearing to Sequential Bilateral Cochlear Implantation in Children-A Within-Subject Comparison
OBJECTIVE:To evaluate the performance changes after sequential bilateral cochlear implantation in a pediatric population of bimodal cochlear implant (CI) users. To evaluate the factors which influence the parental and recipient decision to discontinue hearing aid use and seek a second implant. STUDY DESIGN/METHODS:Retrospective case review, within-subject comparison. SETTING/METHODS:Tertiary referral center. PATIENTS/METHODS:Thirty-one pediatric (<18 yr) bimodal CI users who underwent sequential bilateral CI. INTERVENTIONS/METHODS:Sequential bilateral CI. MAIN OUTCOME MEASURES/METHODS:Parental and/or recipient's reasons for discontinuing their hearing aid and pursuing a second implant, device usage from datalogs, speech understanding in the bimodal and bilateral CI condition. RESULTS:Parents/patients were motivated to pursue sequential bilateral CI based on their positive performance with CI1, the expectation of further improvement with a second CI, and the prospect of having a second independently functional ear. In the bimodal condition, mean word recognition score (WRS), sentence recognition in quiet (SIQ), and sentence recognition in noise (SIN) scores were 87.4, 97.3, and 92.9% respectively. At 1-year post-sequential bilateral CI, the mean WRS, SIQ, and SIN score were 92.7, 98.7, and 97.7%, respectively. The improvement in bilateral CI speech scores compared with bimodal scores was statistically significant for WRS (pâ€Š=â€Š0.015). A ceiling effect limited the ability to detect further meaningful differences on speech perception testing. CONCLUSIONS:The bilateral CI condition demonstrates equivalent or slightly superior performance compared with the bimodal condition. Several non-speech benefits were elicited from parents as reasons for pursuing a second implant. Close monitoring of the residual acoustic hearing, inquiring about the perceived benefits provided by the HA, and early counseling regarding the potential for sequential bilateral CI are important aspects in determining if and when a second implant is indicated.
Cochlear implantation in patients with neurofibromatosis type 2 and other retrocochlear pathology: A review of 32 cases over 25 years [Meeting Abstract]
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