Water penetration of grommets: an in vitro study

Abstract

The insertion of grommets has been one of the most common procedures carried out by ENT surgeons for patients with persistent middle ear fluid. There has always been apprehension at the use of grommets by patients undertaking swimming or other water sports due to concerns of grommet penetration by water into the middle ear. Despite this, no common consensus exists amongst otolaryngologists regarding post-operative advice following grommet insertion. Most studies focus on surface swimming and do not consider other activities such as diving that patients may undertake. This study aimed to determine the hydrostatic head required for water to pass through a grommet using different water-based solutions. These were selected to simulate conditions such as swimming and showering or bathing. An improved model of a grommeted middle ear (based on previous work by Ricks et al.) was constructed using two 5-ml plastic syringes, latex (from a surgical glove), two rubber neoprene membranes and a Shah Ventilation Tube (1.14 mm). Different water solutions were added to the system and the hydrostatic head measured using digital calipers. The results revealed that the hydrostatic head required to penetrate a grommet is lowest using soapy water and highest with distilled water. The differences between chlorinated water and 3% saline were not significant. We hope that this study can be used in conjunction with previous work to better prepare the ENT surgeon in giving suitable post-operative advice following grommet insertion.