high-speed-human-temporal-bone-sectioning-for-assessment-covid-19

High-Speed Human Temporal Bone Sectioning for the Assessment of COVID-19-Associated Middle Ear Pathology

Histopathologic analysis of human temporal bone sections is a fundamental technique for studying inner and middle ear pathology. Temporal bone sections ...

harvest-vestibular-end-organs-under-physiologic-conditions-during

Harvest of Vestibular End-Organs under Physiologic Conditions during Labyrinthectomy

The living human inner ear is challenging to study because it is encased within dense otic capsule bone that limits access to biological tissue. ...

Johns Hopkins University School of Medicine

Bell palsy and traumatic facial nerve injury are two common causes of acute facial palsy. Most patients with Bell palsy recover favorably with medical therapy alone. However, those with complete paralysis (House-Brackmann 6/6), greater than 90% degeneration on electroneurography, and absent electromyography activity may benefit from surgical decompression via a middle cranial fossa (MCF) approach. Patients with acute facial palsy from traumatic temporal bone fracture who meet these same criteria may be candidates for decompression via an MCF or translabyrinthine approach based on hearing status.

Surgical Management of Acute Facial Palsy.

To study the relationship between various electrodiagnostic modalities in acute facial palsy.

Electrodiagnostic testing in acute facial palsy: Outcomes and comparison of methods.

Cerebrospinal fluid (CSF) fistulae originating from the fallopian canal of the facial nerve is hypothesized to arise due to atypical patterns of subarachnoid space extension into the geniculate ganglion or more distal regions along the intratemporal course of the facial nerve, but its pathogenesis remains poorly understood. Although a rare etiology of CSF fistulae of the temporal bone, there are significant clinical ramifications due to the risk of recurrent meningitis, difficulty in identifying the anatomic location of the CSF leak, and technical challenges associated with surgical repair. We present three clinical cases of arachnoid cysts within the geniculate fossa with or without CSF fistulization and provide histopathologic correlates of this rare clinical phenomenon from a human temporal bone collection. The pediatric and adult patients presented suggest differential pathophysiologic mechanisms associated with CSF fistulae. Temporal bone histology reveals atypical patterns of subarachnoid space extension in the fallopian canal that may underlie arachnoid cyst formation and overt CSF leak from the geniculate region.

Perigeniculate arachnoid cysts and CSF fistulae of the fallopian canal: Histopathologic correlates of a rare clinical entity.

Melanin pigmentation is present within the auditory and vestibular systems of the mammalian inner ear and may play a role in maintaining auditory and vestibular function. Melanocytes within the stria vascularis (SV) are necessary for the generation of the endocochlear potential (EP) and decreased EP has been linked to age-related hearing loss. Melanocytes and pigment-containing "dark cells" are present within the vestibular system, but have a less well-defined role. African-American individuals have increased pigmentation within the SV and vestibular system, which is hypothesized to be related to lower rates of age-related hearing loss and vestibular dysfunction. It remains unclear if increased pigmentation confers lifelong protection against hearing loss and vestibular dysfunction.

Comparison of Age-Related Pigmentary Changes in the Auditory and Vestibular Systems Within Mouse and Human Temporal Bones.

 Capillaries within the inner ear form a semi-permeable barrier called the blood-labyrinth barrier that is less permeable than capillary barriers elsewhere within the human body. Dysfunction of the blood-labyrinth barrier has been proposed as a mechanism for several audio-vestibular disorders. There has been interest in using magnetic resonance imaging (MRI) with intravenous gadolinium-based contrast agents (GBCA) as a marker for the integrity of the blood labyrinth barrier in research and clinical settings. This scoping review evaluates the evidence for using intravenous gadolinium-enhanced MRI to assess the permeability of the blood-labyrinth barrier in healthy and diseased ears.  A systematic search was conducted of three databases: PubMed, EMBASE, CINAHL PLUS. Studies were included that used GBCA to study the inner ear and permeability of the blood-labyrinth barrier. Data was collected on MRI protocols used and inner ear enhancement patterns of healthy and diseased ears in both human and animal studies.  The search yielded 14 studies in animals and 53 studies in humans. In healthy animal and human inner ears, contrast-enhanced MRI demonstrated gradual increase in inner ear signal intensity over time that was limited to the perilymph. Signal intensity peaked at 100 min in rodents and 4 h in humans. Compared to controls, patients with idiopathic sudden sensorineural hearing loss and otosclerosis had increased signal intensity both before and shortly after GBCA injection. In patients with Ménière's disease and vestibular schwannoma, studies reported increased signal at 4 h, compared to controls. Quality assessment of included studies determined that all the studies lacked sample size justification and many lacked adequate control groups or blinded assessors of MRI.  The included studies provided convincing evidence that gadolinium crosses the blood-labyrinth barrier in healthy ears and more rapidly in some diseased ears. The timing of increased signal differs by disease. There was a lack of evidence that these findings indicate general permeability of the blood-labyrinth barrier. Future studies with consistent and rigorous methods are needed to investigate the relationship between gadolinium uptake and assessments of inner ear function and to better determine whether signal enhancement indicates permeability for molecules other than gadolinium.

MRI With Gadolinium as a Measure of Blood-Labyrinth Barrier Integrity in Patients With Inner Ear Symptoms: A Scoping Review.

To perform a systematic review to determine if a total score of ≥14.5 (mean score ≥ 2.1) on the ETDQ-7 accurately identifies patients with obstructive Eustachian tube dysfunction (OETD) on impedance tympanometry (peak compliance <0.2 mL or middle ear pressure of -100 daPa) or other objective measures of OETD.

Nicholas S. Andresen

Department of Otolaryngology - Head & Neck Surgery

Johns Hopkins University School of Medicine

High-Speed Human Temporal Bone Sectioning for the Assessment of COVID-19-Associated Middle Ear Pathology

Harvest of Vestibular End-Organs under Physiologic Conditions during Labyrinthectomy

Nicholas S. Andresen

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Otolaryngology - Head & Neck Surgery

Johns Hopkins University School of Medicine

High-Speed Human Temporal Bone Sectioning for the Assessment of COVID-19-Associated Middle Ear Pathology

Harvest of Vestibular End-Organs under Physiologic Conditions during Labyrinthectomy

Department of Otolaryngology - Head & Neck Surgery