Neff, Brian A.

ObjectiveTo ascertain the relationship among vestibular schwannoma (VS) tumor volume, growth, and hearing loss.Study DesignRetrospective cohort study.SettingSingle tertiary center.Subjects and MethodsAdults with observed VS and serviceable hearing at diagnosis were included. The primary outcome was the development of nonserviceable hearing as estimated using the Kaplan‐Meier method. Associations of tumor volume with baseline hearing were assessed using Spearman rank correlation coefficients. Associations of volume and growth with the development of nonserviceable hearing over time were assessed using Cox proportional hazards models and summarized with hazard ratios (HRs).ResultsOf 230 patients with VS and serviceable hearing at diagnosis, 213 had serial volumetric tumor data for analysis. Larger tumor volume at diagnosis was associated with increased pure‐tone average (PTA) (P <. 001) and decreased word recognition score (WRS) (P =. 014). Estimated rates of maintaining serviceable hearing at 6 and 10 years following diagnosis were 67% and 49%, respectively. Larger initial tumor volume was associated with development of nonserviceable hearing in a univariable setting (HR for 1‐cm3 increase: 1.36, P =. 040) but not after adjusting for PTA and WRS. Tumor growth was not significantly associated with time to nonserviceable hearing (HR, 1.57; P =. 14), although estimated rates of maintaining serviceable hearing during observation were poorer in the group that experienced growth.ConclusionLarger initial VS tumor volume was associated with poorer hearing at baseline. Larger initial tumor volume was also associated with the development of nonserviceable hearing during observation in a univariable setting; however, this association was not statistically significant after adjusting for baseline hearing status.

A growing body of clinical and epidemiological evidence supports a specific relationship between vestibular symptoms and migraine. Without a biomarker or complete understanding of pathophysiology, diagnosis of vestibular migraine (VM) currently depends upon symptoms in two dimensions: episodic vestibular symptoms temporally related to migraine symptoms. The Bárány Society and the International Headache Society have recently developed consensus diagnostic criteria. However, many issues remain unsettled, including the type, duration, and timing of vestibular symptoms related to headache that should be required for diagnosing VM. This paper focuses on the challenging third dimension of comorbidity, a frequent cause of diagnostic uncertainty that may confound clinical application and research validation of VM criteria. Several other neurotologic conditions occur more frequently in migraineurs than controls, including benign paroxysmal positional vertigo, Ménière's disease, and motion sickness. Patients with VM also have high rates of chronic subjective dizziness, which may be associated with anxious, introverted temperaments that can affect clinical presentation and treatment response. Broadly inclusive studies of well-characterized patients with other neurotologic and psychiatric comorbidities are needed to fully understand how vestibular symptoms and migraine interact in order to truly validate vestibular migraine, distill its essential features, define its boundaries, and characterize overlapping comorbidities.

Objective:To ascertain long-term hearing outcomes in patients with serviceable hearing following microsurgical resection of sporadic vestibular schwannoma (VS).Study Design:Retrospective cohort.Setting:Tertiary academic referral center.Patients:Forty-three adult subjects with unilateral sporadic VS who had serviceable hearing (American Academy of Otolaryngology–Head and Neck Surgery [AAO-HNS] class A or B) on initial postoperative audiogram following microsurgical resection between 2003 and 2016 with a minimum of two postoperative audiograms available for review.Intervention:Surgical treatment with a retrosigmoid or middle cranial fossa approach.Main Outcome Measure:Rate of maintaining serviceable hearing, as estimated using the Kaplan–Meier method, in accordance with the 1995 and 2012 AAO-HNS guidelines on reporting hearing outcomes.Results:The median immediate postoperative pure-tone average (PTA) and word recognition score (WRS) were 31 dB and 95%, respectively. At last follow-up, the median PTA was 38 dB with a median change of 5 dB from initial postoperative audiogram, and the median WRS was 90% with a median change of 0% from initial postoperative audiogram. Eight patients developed non-serviceable hearing at a median of 4.1 years following microsurgical resection (interquartile range, 2.9–7.0). The median duration of hearing follow-up for the 35 patients who maintained serviceable hearing was 3.1 years (interquartile range, 2.2–7.5). Tumor control was achieved in 41 (95%) patients. The rate of maintaining serviceable hearing at 5 years was 81%.Conclusion:Microsurgical resection provides excellent tumor control and durable long-term hearing in those with AAO-HNS class A or B hearing postoperatively. The paradigm of proactive microsurgical resection—when the tumor is small and hearing is good—hinges on the surgeon's ability to preserve residual hearing in a very high percentage of cases at or near preoperative hearing levels to maintain an advantage over conservative observation with regard to long-term hearing preservation.

Objective: To report the use of multi-frequency intra-cochlear electrocochleography (ECOG) in monitoring and optimizing electrode placement during cochlear implant surgery. An acoustic pure tone complex comprising of 250, 500, 1000, and 2000 Hz was used to elicit ECOG, or more specifically cochlear microphonics (CMs), responses from various locations in the cochlea. The most apical cochlear implant electrode was used as the recording electrode. Study Design: Clinical capsule report. Setting: Tertiary academic referral center. Results: ECOG measurements were performed during cochlear implant surgery in an adult patient with significant residual acoustic hearing. The 500, 1000, and 2000 Hz CM tracings from the most apical electrode showed an amplitude peak at three different instances during the early phase of cochlear implant electrode insertion. These results are consistent with the tonotopic organization of the cochlea. During final electrode placement a slight advancement of the electrode array resulted in a correlated decrease in 250, 500, and/or 1000 Hz CM amplitude. The electrode array was retracted and repositioned which resulted in a recovery of CM amplitude. Intraoperative CM thresholds revealed a correlation of r = 0.87 with preoperative audiometric thresholds. Conclusion: We present a report on simultaneous multi-frequency ECOG monitoring during cochlear implant surgery. Multi-frequency ECOG can be used to differentiate between electrode trauma and the advancement of the apical electrode beyond the CM source in the cochlea.

OBJECTIVE Tumor-associated macrophages (TAMs) have been implicated as pathologic actors in phenotypically aggressive vestibular schwannoma (VS), potentially mediated via programmed death-ligand 1 (PD-L1). The authors hypothesized that PD-L1 is a key regulator of the VS immune microenvironment. METHODS Forty-six consecutive, radiation-naïve, sporadic VSs that were subtotally resected at primary surgery were assessed via immunohistochemical analysis, including analysis of CD163 and PD-L1 expression. Pathologic data were correlated with clinical endpoints, including tumor control, facial nerve function, and complications. RESULTS Baseline parameters were equivalent between stable and progressive post–subtotal resection (STR) VS. CD163 percent positivity and M2 index were significantly increased among tumors that remained stable (34% vs 21%, p = 0.02; 1.13 vs 0.99, p = 0.0008), as well as patients with favorable House-Brackmann grade I or II facial nerve function (31% vs 13%, p = 0.04; 1.11 vs 0.97, p = 0.05). PD-L1 percent positivity was significantly associated with tumor progression (1% vs 11%, p = 0.01) and unfavorable House-Brackmann grade III–VI facial nerve function (1% vs 38%, p = 0.02). On multivariate analysis, PD-L1 was independently significant in all models (likelihood ratio 4.4, p = 0.04), while CD163 was dependent in all iterations. CONCLUSIONS In contrast to prior reports, in this study, the authors observed significantly increased levels of M1, CD163 + TAMs in association with VS that progressed after STR. Progressive tumors are characterized by increased PD-L1, potentially highlighting a mechanism of immune evasion that results in TAM deactivation, tumor growth, and further infiltration of anti-tumor immune cells. Targeting PD-1/PD-L1 may offer therapeutic promise, particularly in the setting of disease control after STR.

Objective: The etiology of sensorineural hearing loss (SNHL) in patients with jugular paraganglioma (JP) whose tumors lack inner ear fistulae or vestibulocochlear nerve involvement is unknown. Recent literature has proposed that occlusion of the inferior cochlear vein may be causative. Herein, we assess the association between radiologic involvement of the cochlear aqueduct (CA) and the development of SNHL. Study Design: Blinded, retrospective review of imaging and audiometry. Setting: Tertiary center. Patients: Adults with JP. Intervention(s): None. Main Outcome Measures: Asymmetric SNHL was assessed continuously as the difference in bone conduction pure-tone average (BCPTA) between ears and as a categorical variable (≥15 dB difference at two consecutive frequencies, or a difference in speech discrimination score of ≥15%). Involvement of the CA was considered present if there was evidence of medial T2 fluid signal loss, contrast enhancement, or bony erosion/expansion. Results: Of 30 patients meeting inclusion criteria, 15 (50%) had asymmetric SNHL. CA involvement was observed in 87% of patients with asymmetric SNHL compared with 13% in those with symmetric hearing (p = 0.0001). Univariate analysis demonstrated that age, sex, and tumor volume were not associated with asymmetric SNHL. The median difference in BCPTA between ears in patients with CA involvement was 21.3 dB HL compared to 1.2 dB HL in those without CA involvement (p < 0.0001). Regression analysis demonstrates that enhancement within the CA is associated with a BCPTA difference of 19.4 dB HL (p = 0.0006). Conclusions: Cochlear aqueduct involvement by JP is associated with SNHL in the absence of inner ear fistula, vestibulocochlear nerve involvement, or brainstem compression. Correlation with operative findings or histopathologic evidence of tumor involvement may validate this intriguing imaging finding.

ObjectiveThe purpose of this article was to provide a combined pathologic and radiologic review of previous pathologically diagnosed facial nerve “hemangiomas” to confirm that these lesions are most characteristic of venous malformations rather than neoplasms.Study DesignRetrospective radiologic, clinical, and histopathologic review of all patients with a previous pathologically diagnosed facial nerve hemangioma of the temporal bone who underwent computed tomography or magnetic resonance imaging (MRI) were included. A consensus radiologic review for characteristic features and pathologic analysis was performed.Materials and MethodsA panel of 4 neuroradiologists retrospectively analyzed CT and MRI exams for 11 facial nerve hemangiomas and provided a consensus agreement on the characteristic imaging features. Concurrently, two neuropathologists reevaluated archived tissue specimens from these lesions and applied additional immunohistochemical and histochemical stains including D240, CD31, smooth muscle actin (SMA), Verhoeff Van Gieson (VVG) and glucose transporter 1 (GLUT1).ResultsLesions were composed of dilated vascular spaces with a simple, CD31‐positive endothelial lining and a smooth muscle component. All lesions were negative for markers found in arterial and lymphatic malformations and infantile hemangiomas. They had characteristic radiologic features previously ascribed to facial nerve hemangiomas. Namely, these lesions are typically T1 isointense or hypointense and T2 hyperintense relative to cerebral cortex and heterogeneously enhance on MRI. Bony canal expansion and erosion, intralesional calcification, and intracranial extension are common.ConclusionsOn the basis of this radiologic and pathologic review, these lesions are best characterized as venous malformations.Level of Evidence4