Pneumatic otoscopy and impedance studies in middle ear diagnosis.

The direct inspection of the tympanic membrane and its movement with Siegle pneumatic otoscopy through the binocular microscope and the electroacoustic measurements of impedance at the tympanic membrane give valuable information in the diagnosis of tympanic membrane and middle ear disorders. Problems such as otosclerosis and tympanosclerosis with ossicular chain fixation, ossicular discontinuities, ossicular chain prosthesis defects and perilymph fistulas, and the problems of middle ear fluid can be identified and differentiated. Frequently a precise diagnosis can be determined prior to surgical exploration. The use of these instruments enables the otologist to anticipate surgical findings and plan a specific procedure, thereby avoiding operative surprises. The routine use of the pneumatic otoscope and an electroacoustic impedance bridge is recommended in every case of suspected tympanic membrane or middle ear disorder, particularly where an operation is being considered. The combined information obtained through use of the two diagnostic techniques is almost always greater than that obtained by either instrument alone. Pressure recordings were made in a series of examinations with the pneumatic otoscope using the ear microscope. These pressures, both positive and negative, are acceptable and well within the range utilized by clinical electroacoustic impedance bridges. Contraindications to the use of pneumatic otoscopy and the electroacoustic impedance bridge are discussed.