ABSTRACT
In 1979, Delgado and colleagues first described the use of evoked compound muscle action potentials to monitor facial nerve function in response to stimulating the intra-cranial portion of the facial nerve. Facial nerve monitoring has proved an invaluable aid during vestibular schwannoma surgery. Three trials tested the hypothesis that facial nerve outcome improved when using intra-operative facial nerve monitoring. The benefit of facial nerve monitoring during surgery for chronic middle ear disease is less certain. Facial nerve injury after otological surgery is rare in experienced hands and there are no randomized controlled trials examining its efficacy. A simple technique for confirming equipment function is described under 'Technique for continuous facial nerve monitoring' below. Monitoring techniques have developed to minimize this interference and amplify only relevant information. Two sets of subdermal platinum or stainless steel needle recording electrodes are inserted into the upper and lower face. The electromyographic electrical response is biphasic.
