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Anatomy and Physiology of Balance
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Nishchay Mehta, Andrew Forge, Jonathan Gale
On the medial surface of the vestibule there is a further bony extension that projects posteriorly called the vestibular aqueduct. The vestibule has two openings on its lateral surface, the oval window superiorly and round window inferiorly.
Nonconventional Clinical Applications of Otoacoustic Emissions: From Middle Ear Transfer to Cochlear Homeostasis to Access to Cerebrospinal Fluid Pressure
Published in Stavros Hatzopoulos, Andrea Ciorba, Mark Krumm, Advances in Audiology and Hearing Science, 2020
Blandine Lourenço, Fabrice Giraudet, Thierry Mom, Paul Avan
Pressure in the two fluid compartments of the labyrinth, the perilymphatic and endolymphatic ones, and ICP equalize through several canals across the temporal bone (cochlear and vestibular aqueducts, and likely venous pathways) (Fig. 8.2).
Jugular Foramen Lesions and their Management
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
The transverse sinus is an important structure in the venous drainage system of the brain, which opens into the sigmoid sinus. Venous flow proceeds via the jugular foramen through the skull base towards the IJV in the neck. Several venous pathways drain into the sigmoid–jugular complex: the superior and inferior petrosal sinuses, the occipital sinus and the mastoid and condylar emissary veins. The most important is the inferior petrosal sinus that contains the effluence of the cavernous sinus and the basilar plexus. The dome of the jugular bulb is in close contact with the floor of the hypotympanum, the vestibule, the posterior semicircular canal, the vestibular aqueduct and the internal auditory canal. The lateral side of the jugular bulb is close to the mastoid (vertical) segment of the facial nerve. The jugular foramen lies in close proximity to the internal carotid artery: only a small osseous spine separates the vertical part of the carotid canal from the jugular foramen (Figures 107.2 and 107.3).
Enlargement of the vestibular aqueduct at cone-beam CT: ELST or EVA?
Published in Hearing, Balance and Communication, 2020
Davide Brotto, Federica Sartorato
First described by Cotunnius in 1761 [1], the vestibular aqueduct (VA) is a bone canal localized in the temporal bone and is considered a part of the bony labyrinth. Its orifice can be found at the hinder part of the medial wall of the vestibule. With a posterosuperior direction, the VA extends towards the posteromedial surface of the petrous portion of the temporal bone [2]. The canal is known to host an outpouch of the membranous labyrinth, the ductus endolymphaticus, ending in a cul-de-sac between the layers of the dura mater within the cranial cavity, the endolymphatic sac [2]. On the contrary, the belief that a vessel is hosted in the canal is quite widespread, although it was proven to be false [3]. As a matter of fact, the vein of the vestibular aqueduct (VVA) was correctly described by Cotugno in 1761 [1] and by Siebenmann in 1894 [4]: the VVA takes an individual bony course parallel to the VA [3]. As a consequence of the above mentioned anatomical relationships, pathologies causing abnormalities of the VA are the abnormal embryological development or the acquired degeneration of the ductus endolymphaticus and/or the endolymphatic sac. The congenital bulging of the endolymphatic sac is supposed to cause the enlarged vestibular aqueduct (EVA), the most frequent malformative cause of hearing loss [5]. On the other hand, a neoplastic degeneration of the cells of the endolymphatic sac is the cause of the development of the endolymphatic sac tumor (ELST) [6].
Dissociated responses to caloric and head impulse stimulation in a case of isolated vestibule-lateral semicircular canal dysplasia
Published in Acta Oto-Laryngologica Case Reports, 2018
Ricardo Wegmann-Vicuña, Octavio Garaycochea, Pablo Domínguez-Echavarri, Carlos Guajardo-Vergara, Reyes García-Eulate, Nicolás Pérez-Fernández
The second finding in the vestibular work-up results raises a very current question in vestibular testing as it is the dissociation between caloric and vHIT results, being the former abnormal and the later normal. This pattern has been found in 20% of patients with dizziness [8] but is more frequent in patients with Ménière’s disease in which it is hypothesized to be due to hydropic distention of the membranous labyrinth in the LSC [11] and ampulla [12]. It has also been reported to be a frequent finding in patients with enlarged vestibular aqueduct [13]. We have shown in our case that this could be a possible explanation based on the MRI findings that were similar to those reported by others [7]. Technical limitations in voxel dimension in our study reduce the ability to image the membranous canal properly. Both techniques differ significantly, but regarding our findings we should also mention another possible source of a dissociated response. Angular VOR fails to compensate at lower frequencies of stimulation as in the caloric test; in order to prolong the peripheral vestibular signal (as seen in constant velocity rotations) a central processing, a velocity storage integrator, has been proposed. Different conditions can modify its function well characterized by a time constant: this is significantly reduced in MD as in other peripheral vestibulopathies [14]. The nystagmus response to the caloric test should be then also reduced as seen in our case. High-frequency angular VOR does not needs of the velocity storage to correctly compensate for head rotations [15].
Developmental performance between pediatric cochlear implantation candidates with and without large vestibular aqueduct syndrome
Published in Acta Oto-Laryngologica, 2021
Yanhong Li, Yang Yang, Wanxia Zhang, Jihang Sun, Bing Liu, Min Chen, Wei Liu, Shanshan Liu, Xiaoxu Wang, Shilan Li, Jie Zhang, Xin Ni
Vestibular aqueduct was regarded as enlarged when the midpoint diameter of the aqueduct was >1.5 mm in the axial view in a CT scan [8]. According to the results of the CT scan, 70 children diagnosed with isolated enlarged vestibular aqueduct and pure mutation of SLC26A4 gene were recruited as the LVAS group. Among the remaining subjects without enlarged vestibular aqueducts, we used propensity matched analysis (PSM), matching factors of gender, age, and hearing threshold, to screen the candidates for the non-LVAS group at the ration of 1:1 (LVAS:non-LVAS). Finally, 70 gender-, age-, and auditory-matched children were recruited as the non-LVAS group. Table 1 summarizes the demographic characteristics of the two groups.