Anesthesia of the tympanic membrane and ear canal by the use of
iontophoresis of local anesthetics is a painless and safe
method of
anesthesia for office myringotomy and polyethylene tube insertion, and possibly for surgical use as well. With the use of guinea pig models, the introduction of 4% lidocaine hydrochloride solution in the middle ear space with
iontophoresis revealed no toxic effects on the eighth nerve, and epinephrine hydrocloride potentiates the effects of lidocaine and has no protective mechanism on the eighth nerve function.