Myringoplasty (type-I tympanoplasty)
Myringoplasty is the simplest of the reconstructive procedures, used where ossicular reconstruction is not intended. The principle is to remove the margin of the tympanic perforation to create a fresh, bleeding edge, and then to close the perforation with a graft. A number of grafting materials have been used, but the one in most popular use in the Western world for many years has been a material called temporalis fascia. This is a membrane of connective tissue covering the surface of the temporalis muscle which is situated in the temporal region very close to the ear. The muscle is easily approached through standard incisions for ear surgery or by way of a hairline incision, and the patient’s own fascia is readily obtained and prepared during the operation. The fascia is perhaps 1mm in thickness and, when slightly dried, is easy to handle. It may be placed in one of two positions. Almost all modern otologists prefer the underlay technique, in which the tympanic membrane remnant is elevated and the graft is placed deep to it (Figure 22). This tends to secure the graft well in position but involves opening the middle ear. A few surgeons still prefer the on-lay technique (Figure 22), in which the outer surface of the tympanic-membrane remnant is carefully denuded of all epithelium, and the graft is then laid on this raw surface. Graft placement is not always so secure, and there is a tendency for the graft to lift laterally away from the tympanic membrane and for the anterior part of the tympanic membrane to be rather blunted by outward migration. In experienced hands, however, the technique is quite satisfactory. What will now be described is the standard underlay technique as practised by most modern otologists.