Quantitative analysis of tympanic membrane disease using video-otoscopy.

Abstract

To perform quantitative analysis of pathological changes in the tympanic membrane using video-otoscopic images. Prospective case-control study. Forty-two ears of children with chronic otitis media with effusion (OME) and 15 ears of normal children were included in this study. Tympanic membrane images were captured and digitized using a Welch-Allyn (Skaneatales Falls, NY) VDX-300 Illumination and Imaging system with S-VHS input to a MIRO DC 30 (Pinnacle Systems, Mountain View, CA) visual board in a Power PC-based computer. These images were visualized and recorded during static and pneumatic pressure changes. Quantitative analysis of tympanic membrane disease was performed using Image Pro Plus Imaging software (Media Cybernetics, Del Mar, CA). The measurements included area of the tympanic membrane and its quadrants, area of tympanic membrane involved by disease, angle formed at the umbo, and length of the malleus versus vertical length of the tympanic membrane. Tympanosclerosis was present in 57% of ears and occurred most frequently in the anteroinferior quadrant, but the maximum area of involvement was in the posteroinferior quadrant. The ratio of the angles formed at the umbo was significantly greater (P = .01) for the OME group compared with the control group. The ratio of the length of the umbo and the vertical length of the tympanic membrane was almost identical for the OME and the control groups (P = .4). Videootoscopic images can be used for quantitative analysis of tympanic membrane disease. The ratio of the posterior angle to the anterior angle formed at the umbo seems to be a more reliable indicator of post otitis media than is a reduced length of the long process of malleus.