Obliterative otosclerosis.

An analysis of 420 consecutive cases of obliterative otosclerosis seen in the Christian Medical College Hospital, Vellore is presented. The proportion of truly obliterative otosclerosis is 33.09 per cent (139 ears). Our male to female ratio in truly obliterative otosclerosis is 1.48:1, while in the non-obliterative group it is 1.34:1. The mean age at onset in the obliterative group was 19.14 while in the non-obliterative group it was 25.60. This is statistically significant (P less than 0.001). The age at presentation was 25.90 in the obliterative group while in non-obliterative group it was 30.86; this is also statistically significant (P less than 0.001). However the time interval between the age at onset and the age at presentation is not statistically significant.