Histology of the perforated tympanic membrane and its muco-epithelial junction.

A histological study was performed on total human tympanic membranes with a central perforation. The specimens originated from 30 consecutive and unselected operations in which a total myringectomy was performed prior to reconstruction by means of a tympanic allograft. Beside excessive thickening of the tympanic membrane in 73%, all membranes showed other histological abnormalities: inflammation (97%), excessive fibrosis (97%), tympanosclerosis (80%), hyperkeratosis (83%), rete riges (43%) and epithelial inclusions (6%). Histological localisation of the muco-epithelial junction showed a medial position in 30%, with extensive middle ear invasion by squamous epithelium in 7%. The surgeon performing myringoplasty should keep these findings in mind and he should closely examine the medial side of the perforated tympanic membrane in order to remove any ingrowing epithelium that otherwise would be trapped.