Myringoplasty: does the size of the perforation matter?

Does the size of a tympanic membrane defect influence the success rate in myringoplasty? Many studies which have suggested that size does not affect results have included only small numbers of patients. After a power analysis to identify the size of groups needed to detect a clinically significant difference between the success rate of small and large perforations, a retrospective study was carried out to answer the question. A retrospective study of 423 myringoplasty-only operations showed that size does influence success; the success rate for small perforations was 74.1% compared with 56.0% for large perforations (P = 0.0003). Size also influences the change in four-frequency air conduction thresholds (small perforations +7.2 dB, large perforations +10.2 dB; t = 2.08, P = 0.039) in successful myringoplasties, a positive value indicating an improvement in hearing. This change is unlikely to be clinically significant. Patients should be made aware of these facts when informed consent is being obtained.