Some pitfalls in the evaluation of auditory function after surgical procedures

Because clinical bone conduction is composed of at least three different mechanisms, two of which are air conduction, uncritical use of the air-bone gap in connection with surgical procedures may give rise to erroneous conclusions. Genuine bone conduction may be influenced by ear pathology and by surgery due to alterations in the mechanical impedance at the site of application of the bone vibrator and at the round and oval windows. The supplementary use of impedance audiometry and advanced speech audiometry is recommended.