Histopathological observations on polyethylene-type materials in chronic ear surgery.

Proplast implants were used in reconstruction of the posterior ear canal wall in one ear and in obliteration of the cavity in two ears. All ears healed well but the canal wall implant became visible in 15 months and had to be removed because of persistant suppuration. The other two implants became visible 3 to 4 years postoperatively. Plastipore TORPs were implanted in two ears undergoing revision surgery. One prosthesis was removed several months later because of infection, and the other 1 year after surgery, as no improvement in hearing had been achieved. Histologically, masses of giant cells were seen in the implants and many cells had engulfed both the vitreous carbon material of Proplast and the white Teflon material of both Proplast and Plastipore. It is concluded that Proplast is unsuitable either for canal wall reconstruction or for cavity obliteration. Plastipore should be used only as a bridge between two ossicles. If the implant must be applied to the tympanic membrane, that end should be fitted with a nonabsorbable bony homograft, which does not cause foreign body reaction.