It is a surgical procedure of ear drum where a small incision is made in the drum to relieve excess pressure and discomfort caused by accumulation of fluid/pus in the middle ear cavity.
A small tube is sometimes inserted which allows adequate aeration of middle ear and prevents re-collection of fluid. The tube gets self extruded in 6-12 months or is removed by the ENT surgeon during a secondary minor procedure.
Without insertion of the tube, the incision heals itself within 3-4 weeks.