Complex sentence: A tympanostomy tube is inserted into the eardrum in order to keep the middle ear aerated for a prolonged period of time to prevent re-accumulation of fluid, as without the insertion of a tube, the incision would heal spontaneously in two to three weeks.
Split into simpler sentences: A tympanostomy tube is inserted into the eardrum in order to keep the middle ear aerated for a prolonged period of time to prevent re-accumulation of fluid. Without the insertion of a tube, the incision usually heals spontaneously in two to three weeks.