ABSTRACTThe efficacy of hyaluronic acid when utilized in tympanoplasty was investigated in a multicenter, randomized, prospective patient blinded study. Of the 117 patients who completed the study, a majority (76) were treated with myringoplasty, 26 with myringoplasty combined with ossiculoplasty, and 15 with ossiculoplasty alone. The patients were evaluated by the operating surgeon up to 3 months following surgery, when the final assessment was made. The patients were divided into three groups: group 1 was treated with hyaluronic acid, 1 percent; group 2 with hyaluronic acid, 1.9 percent; and group 3 constituted the control where no hyaluronic acid was used at all. In the two test groups, utilizing hyaluronic acid, no gelatinous sponge was allowed to be left in the middle ear after surgery, whereas the control group was operated according to standard principles. The three groups were compared after the termination of the study as regards quality of healing and their hearing results. It could be concluded that the healing process within the middle ear and the tympanic membrane, as well as the hearing ability, was similar in all three groups. Thus no statistically significant differences could be obtained between the patient groups in which hyaluronic acid had been utilized in any concentration and the control group operated according to standard routine. This finding does not exclude, however, that hyaluronic acid might have a place in tympanoplastic surgery of today, since the long-term results were not evaluated here.