Interrelations between the middle and inner ear in otitis media

This article reviews the importance of the round-window membrane in exposing the labyrinth to or protecting it from the toxic effects of otitis media. Characteristics of the immune system in the human middle ear and middle-ear mechanisms against bacteria are explained. The role of bacteria and bacterial products in inner-ear damage is detailed, and related pathological events are described. The hypothetical role of inflammatory mediators in bacteria-induced inner-ear toxicity is particularly emphasized. Clinical conditions causing these events are detailed, and the most frequently involved microorganisms are mentioned. Finally, round-window membrane macroscopic and microscopic anatomy is discussed, and considerations about the exact role of membrane inflammation--protection versus damage of the inner ear--are expressed.