[Involvement of the tympanic bone in chronic otitis (44 cases)].

44 cases of tympanic involvement in the context of chronic otitis are described. 34 occurred during active chronic otitis. This is a rare possibility (approximately 4% of our own cases of chronic otitis). The following may be mentioned amongst them: 21 cases of osteitis, for which the following concepts should be borne in mind: the extreme severity of the chronic otitis responsible, in most instances, ears which had undergone multiple surgery (17/21), lesions exclusively of osteitis, but very extensive in 2/3 of cases (14/21). 7 cases of osteolytic disease, occurring severe or atypical cholesteatomatous chronic otitis and quite often involving associated osteolysis affecting the main VII, the promontory, the bulb of the internal jugular vein, or even the carotid canal. 4 cases of diffuse sub-obstructive osteomatous disease of the walls of the E.A.M., "progressive" development of which over several months was noted in 3 cases. Finally, 2 cases of mixed disease: (osteitis--osteomatoma and osteitis--osteolysis). 8 cases occurred following myringoplasty: this is a rare eventuality (approximately 1%), 1 case only of osteolysis due to iatrogenic cholesteatoma, 7 cases of osteitis, either highly localized and not preventing further myringoplasty (4 cases), or very extensive, finally resulting in a vast evacuation cavity. In 2 cases, a malformation is the origin of involvement of the tympanic at the origin of chronic otitis was felt probable, without it being possible to reach any definite conclusion concerning auriculobranchial fistula or Huschke foramen.