Anesthesia of the human tympanic membrane by iontophoresis of a local anesthetic

Iontophoresis has been reported as a safe method of tympanic membrane anesthesia but data concerning variations and advances in technique are not available. Normal volunteers were used to determine the effects of varying canal preparation, epinephrine concentration, current level and duration. The two optimal techniques were compared in two groups of ten volunteers. A similar duration of anestheia (90 to 115 min.) was found for both techniques. Clinical application of two techniques for the purpose of myringotomy and/or ventilation tube placement was done in 60 ears of 49 selected private patients with middle ear effusions. Techniques were used at random in the first 23 ears with equal success. The newly developed dry canal preparation method using lower current and longer time was preferred, because of convenience and added safety, in the last 37 procedures. Failure of anesthesia occurred once with acute otitis media and once due to electrode displacement. Fifty‐eight procedures resulted in successful myringotomy and/or tube placement. Proper case selection, prevention of technical problems, advantages, and practical limitations of this anesthesia method are discussed.