Microscopic versus otoendoscopic examination of the tympanic membrane using digital imaging and objective assessment

Abstract

Objectives. The microscope and oto-endoscope are the standard tools for clinical assessment of the tympanic membrane (TM). We aim to compare the adequacy of the tympanic membrane visualisation between methods. Method. Healthy adult volunteers with no previously known ear pathology were recruited following ethical committee approval. The senior author conducted the examinations. We used an operating microscope fixed to magnification ×4, and a 0 degree oto-endoscope connected to a Storz Tricam wired to a computer desktop with digital imaging capture software. Video clips were recorded until the clinician ensured complete clinical examination. Three different assessors conducted assessment using objective criteria and scoring system of the video clips separately. Results. 42 ears were examined in 21 subjects producing 84 video clips. Statistical analysis was conducted using SPSS 12. The inter-observer reliability measured using Cronbach's alpha co-efficient is 0.831, showing reliable agreement between the different 3 assessors. There was near complete agreement on the visualisation of the posterior ½ of the TM in all the clips. The whole TM and the anterior½ measured by Fisher's exact test showed significant difference 0.001 and 0.001 in favour of the oto-endoscope. There was no significant difference in assessment of TM position. Although the microscopes now have built in camera systems, we accept that the three dimensional view through binocular microscopy is projected as a flat two-dimensional view on the monitor and video clip. Conclusions. In the assessment of normal ears, the oto-endoscope provides a more complete visualisation of the eardrum than the microscope.