Dural Venous Sinus Arachnoid Granulations in Patients with Pulsatile Tinnitus.

OBJECTIVE: To determine the relationship, if any, between dural venous sinus arachnoid granulations (AGs) and pulsatile tinnitus. STUDY DESIGN: Retrospective case-control study. METHODS: Between October 1999 and March 2020, magnetic resonance imaging of patients with tinnitus (pulsatile [PT] and nonpulsatile [NPT]) were assessed for the presence of dural venous sinuses AG. During the same interval, patients with AGs found incidentally on all magnetic resonance imagings ordered without an indication of tinnitus were reviewed. Demographic variables recorded included patient age, sex, race, body mass index, and a history of idiopathic intracranial hypertension (IIH) or obstructive sleep apnea. Location of AGs, when present, were recorded. RESULTS: A total of 651 (PT 250, NPT 401) were found to have AGs. AGs had a higher prevalence in PT patients (10.4% [n = 26]) versus NPT patients (0.3% [n = 1]; odds ratio, 31.0; confidence interval 4.1-234; p < 0.001). Of the 77,607 patients who had an indication for imaging other than tinnitus, 230 patients (0.30%) were found to have incidental AGs, suggesting that the NPT cohort was an adequate control. Patients with PT were more likely to have a higher body mass index, be female, be non-White, and have an existing diagnosis of IIH. For all patients with AGs, AGs were more likely to be found in the lateral sinuses (i.e., sigmoid, transverse) in the PT group (odds ratio, 8.1; confidence interval, 1.1-61.1; p = 0.0218). CONCLUSIONS: This study evaluates the association between AG and PT, finding higher rates of AG in patients with PT than in NPT. However, despite the increased prevalence of AG in patients with IIH, these data combined with existing literature would suggest that AGs are not necessarily the missing link to explain PT pathophysiology in IIH.

Quality of Otology and Neurotology Research in Otolaryngology Journals.

OBJECTIVE: To identify trends in the quality of otology studies published in general otolaryngology journals over a 20-year period. STUDY DESIGN: Retrospective analysis. METHODS: Otologic and neurotologic papers from 1997, 2007, and 2017 were identified in the three general otolaryngology journals with the highest Eigenfactor scores: the Laryngoscope, European Archives of Otorhinolaryngology, and Otolaryngology-Head and Neck Surgery. The studies were reviewed and assigned level of evidence (LoE) based on standards set by the Centres for Evidence Based Medicine (CEBM). One-way analysis of variance were calculated with a 95% bootstrap sensitivity analysis performed. RESULTS: A total of 786 otology articles were reviewed for level of evidence, of which 557 (70.8%) were original, clinical research, eligible for LoE assignation. Total publications increased for each year in all three journals. Both the absolute number and proportion of high evidence studies (level of evidence 1 and 2) increased with respect to time in all three journals. Lower evidence studies (level of evidence 3, 4, or 5) made up 66.8% of total publications in 2017. There was a reduction in average level of evidence (towards higher quality evidence) by 0.431 units from 1997 to 2017 (Diff = -0.431 between 1997 and 2017, p < 0.001). There was no significant difference in rate of change of level of evidence between 1997 and 2007 and 2007 and 2017 (0.033, p = 0.864). CONCLUSION: Over a 20-year period the number of total publications increased with time. The majority of otology publications in 2017 were lower evidence studies, though significant increases in the number and proportion of high evidence studies in general otolaryngology journals were observed throughout the study period.

Activation of the rat olfactory bulb by direct ventral stimulation after nerve transection.

BACKGROUND: The aim of this study was to demonstrate how direct electrical stimulation can activate the olfactory bulb after denervation of the olfactory nerve input. METHODS: Sprague-Dawley rats (n = 5) were anesthetized and olfactory bulbs exposed. Olfactory nerves were transected by passing a Teflon blade between the cribriform plate and ventral surface of the bulb. A cochlear implant electrode array was used to stimulate 6 different positions along the ventral surface of the olfactory bulb. Biphasic constant-current pulses were used (50-1000 µA, 50-1000 µs) to stimulate the bulb, and a 16-electrode paddle array was used to record localized negative field potential responses at the dorsal surface of the bulb. RESULTS: Localized negative field potentials were reliably obtained using biphasic, 500-µA, 200-µs pulses. A shift in stimulating position by 1 mm resulted in a significant change in the dorsal field potential. CONCLUSION: Direct stimulation of the deafferented olfactory bulb was effective in generating localized field potential responses. These findings support the potential use of direct electrical stimulation for the treatment of anosmia.