The SMTL have been working with Consultant ENT surgeon Mr Dave Owens and one of his ENT registrars to undertake in vitro assessments of the hydrostatic head required to penetrate grommets. 

The insertion of grommets is a common procedure in children in the UK, and patients frequently express concern about the impact of the procedure on  their ability to participate in swimming and other water-based activities.  Currently there is little information available regarding the actual likelihood of water penetrating through a grommet.

In the laboratory, a novel model was constructed to replicate a grommet inserted through a tympanic membrane.  Four test solutions (deionised water, sodium chloride, 10% soapy water and 10ppm chlorinate water) were applied to the model at a constant rate until bubbles and droplets were observed at the outlet of the grommet.  The hydrostatic head at these points of breakthrough was then recorded.

Results indicate significant differences in the breakthrough pressures for the various test fluids.  A paper is being prepared for publication.