What are small temporary tubes placed in the ear during surgery to help drain fluid?

The answer is correct because grommets are indeed small tubes that are inserted into the eardrum to facilitate the drainage of fluid from the middle ear. This procedure is commonly performed in cases of frequent ear infections or fluid accumulation, helping to equalize pressure and prevent further complications. Grommets allow air to enter the middle ear while allowing fluids to escape, promoting better ear health and function.

As for the other options, while stents and catheters have distinct medical uses, they do not pertain specifically to ear surgery or drainage of middle ear fluid. Tympanostomy tubes, although similar in function to grommets, refer to a broad category of tubes inserted into the tympanic membrane. Grommets are a specific type or brand of tympanostomy tubes, often used interchangeably but typically known by the name grommets in common vernacular.