A long-term review of the Shah Permavent tube.

A retrospective study of 74 Shah Permavent tube insertions is presented. These were inserted into 74 ears of 55 patients during the period between 1985 and 1988. At the time of review, 35 tubes had extruded spontaneously, 11 tubes had been removed for recurrent infections, 10 tubes had been removed electively and 10 tubes were still in situ. On examination of the ears approximately 12 months after the tubes had extruded, the overall rate of tympanic membrane perforation was 18.2 per cent. In ears in which the Permavent tube extruded spontaneously the perforation rate was 22.2 per cent. In ears which the tube was removed because of infection the perforation rate was 20.0 per cent. However in ears in which the tube was removed electively the perforation rate was zero. This finding has implications in the use and management of long-term ventilation tubes.