[Reconstruction of the ossicular chain: Plastipore prosthesis compared with autogenous and allogenic ossicles (author's transl)].

Morphological and audiological early and late results after reconstruction of the ossicular chain with Plastipore prosthesis (TORP's and PORP's) were compared with those achieved by using autogenous or allogenic ossicles. In particular 32 tympanoplasties with TORP's were compared with 25 cases of columella and 29 PORP cases with 75 interpositions. Only Plastipore prostheses were extruded, up to now in 11.4% of cases. The final extrusion rate will be even higher since perforations of the fascia graft or the drum over the head of the prostheses as signs of imminent extrusions were noted in 9.8% of tympanoplasties at the end of the 2-year follow-up period. However, only in one third of tympanoplasties cartilage had been interposed between the head of the prosthesis and the fascia graft or drum. Audiological results, early as well as late ones, using the mean postoperative air-bone gap as criterion of success, showed no statistically significant differences between the compared groups. Only the comparison of the mean air-bone gaps in late results versus the preoperative values seemed to favour the PORP group over the interposition group. In some PORP cases, however, greater reduction of the air-bone gap was caused by postoperative deterioration of the bone conduction threshold level. In addition, hearing gains were more lasting in the interposition than in the PORP group. Because of the high extrusion rate and the fact that the audiological results were not significantly better than in the compared groups we will cease using PORP's and will employ TORP's only with careful interposition of cartilage and then only in selected cases with good tubal function.