ELECTROMYOGRAPHIC FACIAL-NERVE MONITORING DURING RESECTION FOR ACOUSTIC NEURINOMA UNDER MODERATE TO PROFOUND LEVELS OF PERIPHERAL NEUROMUSCULAR BLOCKADE

The facial nerve is monitored intra-operatively using electromyography to identify:and prevent damage during the excision of an acoustic neu rinoma. In order to determine whether a profound level of peripheral n euromuscular blockade could be achieved without compromising facial el ectromyographic monitoring, 11 patients undergoing resection of acoust ic neuroinoma were studied. After induction of anaesthesia, an infusio n of atracurium was administered to reduce the integrated electrically evoked muscle potential (EEMP) of the hypothenar eminence by 70-100%. The facial nerve was directly stimulated in the surgical field and th e facial evoked muscle potentials (EMPs) we re recorded. Even under co mplete peripheral neuromuscular blockade (i.e. no electrically evoked muscle potential measurable over the hypothenar eminence, no palpable hypothenar muscle response) it was possible to evoke facial muscle ele ctromyographic responses by stimulation of the facial nerve.