Destruction of ossicles in chronic otitis media.

The purpose of this study is to investigate the differences in the destruction of ossicles in chronic ear disease caused solely (monoinfection) by one of the most common three bacteria, namely Staphylococcus aureus, Pseudomonas aeruginosa or Proteus strain. Material included 337 cases from 1,093 radically operated ears both with cholesteatoma and without cholesteatoma and in addition cholesteatomatous ears without signs of infection since diagnosed. In 190 ears with cholesteatoma but without discharge the ossicular chain was found damaged at the time of operation in 75 per cent and in 147 discharging ears with cholesteatoma in 79-97 per cent. In infected ears without cholesteatoma the chain was broken in 59-78 per cent. In all groups the most extensive lesions were caused by Proteus strains. This was also the fact in microscopic studies concerning extension and severity of histopathological findings. It seems to us that vascular bone erosion caused by active granulation tissue, the process triggered initially by infection, is the main mechanism for destruction of ossicles both in cholesteatomatous and in non-cholesteatomatous ears. From the histological point of view the ossicles in ears with Staphylococcus aureus and Proteus strains can be so destroyed that their use for autografts is questionable.