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Electrophysiological characterization of pre‐ and postoperative facial nerve function in patients with acoustic neuroma using electrical and magnetic stimulation techniques
Author(s) -
Rösler Kai M.,
Jenni Walther K.,
Schmid Urs D.,
Hess Christian W.
Publication year - 1994
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880170209
Subject(s) - facial nerve , palsy , medicine , neuroma , electrophysiology , stimulation , electromyography , acoustic neuroma , facial paralysis , electroneuronography , facial muscles , surgery , cranial nerve disease , anesthesia , anatomy , pathology , eye disease , physical medicine and rehabilitation , alternative medicine
Facial nerve function was examined in patients who underwent posterior fossa surgery for unilateral acoustic neuroma. Examinations took place prior to surgery ( n = 47 patients), early after surgery (0–12 days, n = 16 of 47 patients), and late after surgery (187–1505 days, n = 29 of 47 patients). Clinical signs of facial palsy were present to a variable extent in 13 of 47 patients before, in 12 of 16 patients early, and in 18 of 29 patients later after surgery. Electrophysiologically, the facial nerve was stimulated electrically at the stylomastoid fossa and magnetically at its proximal intracanalicular segment. In addition, the faceassociated motor cortex was stimulated magnetically. In patients with facial palsy, any of these stimulation methods resulted in a decreased amplitude of the response in the nasalis muscle. The decrease showed a linear relationship to the clinical grade of palsy, pre‐ and postoperatively. Corticomuscular latencies remained unchanged. We conclude that: (i) the electrophysiological characteristics of facial nerve lesions due to compression by acoustic neuromas or due to a complication of neuroma removal are those of a purely axonal neuropathy; (ii) the three stimulation techniques have a similar diagnostic yield, thus making the use of all three of them redundant; and (iii) the electrophysiological techniques allowed no prediction of the final facial nerve function. © 1994 John Wiley & Sons, Inc.