New perspectives in myringoplasty.

Until 1950 the treatment of a perforated eardrum consisted of covering the drum permanently with artificial material. Since then a surgical technique to establish a functional reconstruction of the eardrum was developed (myringoplasty). A survey of the biological grafting materials used in this technique is given. Biodegradable and non-degradable synthetic materials may prove to be a valuable supplement of the existing biological grafting materials. Artificial eardrums made from several biodegradable poly(alpha-hydroxy acids) and poly(alpha-amino acids) and made from a number of microporous poly(tetrafluorethylene) membranes and from a microporous bisphenol-A poly(carbonate) membrane were implanted into the ears of rats and dogs and as a reference subcutaneously. The implants were histologically examined for periods up to one year. From the biodegradable polymers studied poly(beta-benzyl-L-aspartate-co-L-leucine) 50/50 evoked the least tissue reaction and the newly formed eardrums were the best in terms of thickness and overall integrity. The formation of a reinforced eardrum may be accomplished by the support of an inert, very thin, highly porous poly(tetrafluoroethylene membrane) preferably implanted as a composite graft with a biodegradable polymer.