Thickness of the Human Round Window Membrane in Different Forms of Otitis Media

Abstract

\s=b\The thickness and morphologic characteristics of the round window membrane were evaluated in temporal bones from normal subjects as well as those with serous otitis media, purulent otitis media, and chronic otitis media. Temporal bones were studied in chronological order in six age ranges to determine the possibility of age-related differences. No significant difference in the mean thickness of the round window membrane was observed in terms of age groups in normal temporal bones or temporal bones from patients with otitis media; however, a significant difference in the mean thickness was observed in the various forms of otitis media compared with the normal round window membrane in all age groups. The membrane was thickest in patients with chronic otitis media when compared with that in normal subjects or those with serous or purulent otitis media. The epithelial layer (including the subepithelial space) and the fibrous layer were measured individually to determine in which layer the change in mean thickness occurred. These measurements showed an involvement of all layers of the round window membrane in those groups with otitis media, with maximal involvement of the combined epithelial layer and subepithelial space. (Arch Otolaryngol Head Neck Surg 1987;113:630-634) The physiologic role of the round window membrane as a phase dif¬ ferential in permitting labyrinthine fluid to move under the influence of the stapes is widely accepted.13 It is the process of diffusion through the round window membrane, however, that has attracted the attention of

Pathological Features of Healing of a Ruptured Human Round Window Membrane

“…The average thickness of the human RWM is between 40 and 70 Ìm [3]. The thickness of the layers of the RWM, especially the epithelial layer and the subepithelial connective tissue layer, is known to increase with otitis media, but no significant differences in the mean thickness of the RWM of normal temporal bones have been attributed to aging [7].…”

“…Many studies have been done on the anatomy, function, and permeability of the RWM, both in animals [1][2][3][4][5] and in humans [6,7]. Clinical aspects of RWM rupture, such as perilymphatic fistula, have been reported, however, the pathological aspects of its healing process have not been clarified.…”

Gentamicin is Primarily Localized in Vestibular Type I Hair Cells after Intratympanic Administration

“…Although type II hair cells appear to be preserved, they may lose their stereociliary bundles and the ability to transduce head acceleration (Hirvonen et al 2005). The gentamicin lesion in the chinchilla may be more severe than that in humans due to the thinner round window membrane in the chinchilla (Sahni et al 1987). Further studies delivering less of the drug to the chinchilla labyrinth might demonstrate a lesion that is more physiologically restricted to irregular units.…”

Complex modulus of round window membrane over auditory frequencies in normal and otitis media chinchilla ears

“…AOM induces morphological changes of the middle ear tissues, including the tympanic membrane (TM), stapedial annular ligament and RWM, which have been observed in patients and experimental animal models (Sahni et al, 1987;Goycoolea, 1995;Schachern et al, 2008;Yoon and Hellstrom, 2002). Recently, an AOM model of guinea pig induced by Streptococcus pneumonia was created and the changes of RWM mechanical properties were reported by Gan et al (2013).…”