Delayed facial nerve paresis following acoustic neuroma resection and postoperative vasoactive treatment.
OBJECTIVE
Delayed facial nerve paresis is a well known clinical phenomenon following acoustic neuroma surgery, typically occurring early during the postoperative course. The clinical course of the delayed facial nerve paresis and intraoperative electromyographic (EMG) signals were evaluated in a subgroup of patients who underwent vasoactive treatment for preservation of hearing and developed secondary deterioration after termination of treatment.


METHODS
Between 1990 and 2001 seven patients were identified who received vasoactive treatment for preservation of hearing and developed a delayed facial nerve paresis after termination of medication. Intraoperative facial nerve EMG activity was analyzed in six patients.


RESULTS
All patients developed a delayed facial nerve paresis between 2-5 days following termination of a 10 day treatment consisting of HES and nimodipine. Medication was re-initiated and the facial nerve paresis improved in all patients. In two patients intraoperative EMG signals revealed "A-trains" waveform patterns, which are highly suggestive for an immediate postoperative facial nerve paresis, whereas in four patients no pathognomonic EMG patterns could be recorded.


CONCLUSIONS
The delayed onset of a facial paresis following termination of vasoactive treatment points to a disturbed microcirculation of the nerve as the main pathophysiological feature. Two groups could be identified on the basis of intraoperative EMG activity. In one group with presence of "A-trains" medication apparently masked the onset of an immediate postoperative facial nerve deficit. Four patients without "A-trains" did not develop a typical delayed facial nerve paresis during vasoactive treatment, but thereafter. The time lag between termination of treatment and onset of a delayed palsy points to a protective effect due to improved microcirculation.
Scheller
C
C
Neurochirurgische Klinik der Universität Erlangen-Nürnberg, Germany.
Strauss
C
C
Fahlbusch
R
R
Romstöck
J
J
D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D005155:Facial Nerve Diseases / Q000139:chemically induced / Q000209:etiology* / Q000503:physiopathology; D005158:Facial Paralysis / Q000139:chemically induced / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications* / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D009553:Nimodipine / Q000009:adverse effects* / Q000627:therapeutic use; D011183:Postoperative Complications / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000009:adverse effects* / Q000627:therapeutic use
D014665:Vasodilator Agents; D009553:Nimodipine