Several factors are known to affect the length of time a ventilation tube remains in the tympanic membrane. These include the design of ventilation tube, the insertion technique and the presence of intercurrent infection. In addition there are theoretical reasons to suggest that a ventilation tube placed superiorly should remain longer than one placed inferiorly. A randomised prospective study was undertaken on 54 children to test this theory. It showed that there is no significant difference in the extrusion rates for a particular type of ventilation tube (Shah grommet) when comparing the anterosuperior quadrant with the anteroinferior quadrant of the tympanic membrane.