Growth rate and recurrence of residual epidermoid cholesteatoma after tympanoplasty.

One hundred and forty-one consecutive patients with chronic otitis media and cholesteatoma treated mainly by open surgical techniques between 1965 and 1972 were studied to investigate the phenomenon of residual cholesteatoma. The average rate of emergence of residual cholesteatoma was 0.25% of the cases per month during the first 5 years, after which the rate of discovery almost ceased. Observed cumulative frequencies of recurrence were 1.4% at 10 months, 14.9% at 5 years and 17.0% at 8.3 years postoperatively. The null hypothesis of no apparent predilection of cholesteatoma for recurrence at any one site was retained. Parameters of growth rates of epidermoid cysts arising from residual cholesteatoma were estimated. Epitympanic cysts grew fairly rapidly, doubling in diameter every 10 months. Mastoid cysts were slower, doubling in diameter every 25 months. Results for the mesotympanum were inconclusive. The practical implications of this information for the management of future cases is discussed.