There are 4 main types of ventilation tubes used during a tympanostomy – Long Armstrong tubes, Donaldson tubes, Shepard tubes and straight tubes, based on shape. The type of tube used during the surgery depends on the severity of the condition, the length of the patient’s ear canal, the amount of time the tube is expected to stay in the ear canal, etc. Ear tubes are usually made of silicone, plastic, or metal.