376 THE EAR sometimes total loss of hearing, in under 5 per cent of cases. Because of this risk to the hearing the operation should only be carried out on the ear with the poorer hearing. COMPLICATION. The most important complication is loss of hearing and this may occur at the time of the operation but it may not occur until many A B Fig. 197. A, Line of meatal skin incision. B, Exposure of the tympanic cavity. Fig. 198. A, Vein graft and polythene tube operation; B, Fat and wire stapes prosthesis; C, All-Teflon or Teflon-wire piston. months later. For this reason operation on the second ear should only be considered after at least 6 months, and many surgeons believe that opera- tion on the second ear should never be performed. Sudden hearing loss is particularly liable to occur after sudden changes in pressure, and patients should avoid diving and only fly in pressurized aircraft.