Grommet tube is used in -
In some cases of myringotomy, a ventilation tube, also known as grommet or tympanostomy tube, is inserted through myringotomy incision to allow future drainage of the fluid.
The most common indication for myringotomy and grommet insertion is serous otitis media also known as secretory otitis media or mucoid otitis media.
However, it should be kept in mind that SOM is not the only indication for myringotomy with grommet insertion. Other indications are :-


Recurrent acute otitis media (three or more significant ear infections within a six month period).
Chronic otitis media with effusion
Complications of acute otitis media
Tympanic membrane abnormalities (atelectasis or retraction)
Conditions predisposing to eustachian tube dysfunction
Secretory otitis media
Mucoid otitis media
Serous otitis media
All of the above