_Excision of the stricture._ The auricle is reflected forward and the preliminary steps of the operation are performed as already described for removal of a deep-seated exostosis (see p. 319). The surgeon makes a transverse incision with a knife through the fibrous portion of the auditory canal, just external to the stricture, and carries it right round the meatus, thus separating the outer portion of the membranous from the bony canal. The fibrous portion is now pulled outwards by means of a retractor, and the thickened tissue, forming the stricture, is peeled off from the surrounding bony meatus with a small periosteal elevator and so removed. If the stenosis is partially due to thickening of the walls of the canal itself, it may also be necessary to chisel away a considerable portion of its upper posterior part. After completion of the operation a clear view of the tympanic membrane should be obtained. In this operation a considerable portion of the bony canal is denuded of its epithelial lining membrane, so that there is a special tendency to the re-formation of cicatricial tissue. To prevent this taking place two methods may be employed:--(1) If much of the upper posterior wall of the bony meatus be removed, a post-meatal flap should be made and kept in position by means of a catgut suture carried through the skin behind the auricle. The formation of such a flap is described as a step in the complete mastoid operation (see p. 401). (2) If no bone be removed, the membranous portion is replaced _in situ_, the posterior auricular wound closed, and as large an india-rubber tube as possible is inserted into the meatus. A week or ten days later, as soon as granulations begin to form, skin-grafting may be undertaken (see p. 410). If grafting be not successful, the india-rubber tube or silver canula must be kept constantly within the meatus (only being removed for cleansing purposes) until healing takes place. _The complete mastoid operation_ is indicated in the case of stenosis occurring in chronic middle-ear suppuration if symptoms of retention of pus occur. In acute middle-ear suppuration, however, every attempt should be made to avoid operation, as the lumen of the auditory canal may again become patent after the acute inflammation has subsided. OPERATIONS FOR ATRESIA Atresia of the external meatus may be either congenital or acquired. =Indications.= (i) _In congenital cases_ operation is only justifiable if the atresia is due to a _membranous web_ situated in the outer part of the auditory canal and if, as a result of tuning-fork tests and of inflation through the Eustachian tube, it is fairly certain that the middle ear is normal.