[Atrophy of the tympanic membrane in contact with hydroxyapatite prosthesis: physiopathologic approach]

The implantation of ossicular replacement prothesis made of dense hydroxyapatite (HA) appears to be a wider method of reconstruction of ossicular chain damaged by suppurative processes or surgery. A review of 19 patients who underwent implantation of HA prosthesis disclosed 4 cases of extrusion and 3 cases of atrophy. When X-ray diffraction analysis of explanted commercially available prosthesis made of dense HA was compared with the results with porous implants and with HS powder employed in the manufacture of both, is suggested that tympanic membrane atrophy could be caused by mechanical and/or chemical factors.