The etiology of chronic otitis media.

Various current theories regarding the aetiology of chronic otitis media are considered in detail. The concept that it originates from an acute middle ear infection no longer appears tenable. Recent experimental work has demonstrated the role of invading skin causing invasive osteitis. It is postulated that in some instances osteitis may follow erosion of the metal skin and proceed to widespread chronic disease of the temporal bone. The important difference between obstruction and inadequacy of the Eustachian tube and the significance of the latter in chronic middle ear disease is emphsized. The Eustachian mechanism of cholesteatoma formation may best be studied by observing the development of retraction pockets following tympanoplasty.