Local Anesthesia of the Ear by Iontophoresis

Abstract

The use of iontophoresis to introduce lidocaine into the external ear had no adverse effect upon the guinea pig's ear as measured by their alternating current cochlear potentials. Iontophoresis of lidocaine filling the middle ear space also did not affect the guinea pig's cochlear potentials. Iontophoresis of cocaine in the middle ear produced a drastic reduction of the cochlear potential. Iontophoresis of lidocaine in the external ear of humans produced anesthesia of the eardrum. The depth of anesthesia in the humans was sufficient as to permit the execution of painless myringotomies. Using iontophoresis, anesthesia of the human ear canal could only be produced when the eardrum was prevented from serving as an electric current path.