Answer continued...
The answer above posted before I had a chance to edit it. Sorry about that!
And sorry if it is hard to understand. Please post again with questions. Thanks!
It is extremely common for cats to get aural hematoma's over and over again if the inciting problem is not controlled. Inciting problems can be food or environmental allergies causing susceptibility to yeast or bacterial ear infections, ear mites, and less commonly, ear foreign bodies.
If the inciting cause cannot be determined it would be best to stop the itching and pain using Prednisolone or other steroids antihistamines, topical ear medication. If there is a liquidy sound in your cats ear it may be pus. A culture and sensitivity should be performed on the discharge and appropriate oral and ear antibiotics given. Replacement of the sutures after draining the pinna should also be performed. Steroids are necessary to minimize shaking of the head, or ears and scratching, or the hematoma will never heal!
Non absorbable sutures may have been used since even absorbable sutures would have to be removed before they become absorbed in the ear, since the ear is so thin and has so few layers than absorbable sutures would never become absorbed even if left in the 6 weeks to 2 months that it takes the body to absorb them.