Radiographic Differences between the Affected Ears and Non-affected Ears in Unilateral Meniere's Disease

Schüller projection films and CTs encompassing the lateral semicircular canal were obtained in 22 patients with unilateral Meniere's disease ; similar procedures were performed on 16 patients with unilateral chronic otitis media as controls. The distance between the posterior semicircular canal and the posterior petrous surface (P-P distance) was measured in the CTs, and the distance between the capsula ossea labyrinthi and the sigmoid plate (C-S distance) in the Schuller projections. The statistical differences between the affected ears and the non-affected ears were then calculated in both Meniere's disease and chronic otitis media. The correlation between the P-P distance and the C-S distance was also determined.1) In the affected ears in unilateral Meniere's disease, P-P and C-S distances was significantly shorter than in the non-affected ears. No correlation was found between the P-P distance and the C-S distance.2) The C-S distance was shortest in the affected ears of patients with chronic otitis media. The C-S distance appeared to be influenced by middle ear infection : apparent differences due to the radiological projection angle must be taken into consideration.3) The P-P distance appears to be more useful than the C-S distance for the evaluation of Meniere's disease.