Partial neuromuscular blockage levels with mivacurium during mastoidectomy allows intraoperative facial nerve monitoring.
BACKGROUND
Facial nerve monitoring during otologic surgery is helpful for facial nerve preservation, but its usage is closely related to anesthetic procedures.


OBJECTIVE
The aim of this study was to investigate the effectiveness of mivacurium-based partial neuromuscular blockade on facial nerve monitoring during otologic surgery.


METHODS
Forty-three patients scheduled for elective otologic surgery (mastoidectomy with and without tympanoplasty) participated in the study. After induction with propofol 2-3 mg x kg(-1), remifentanil 1 microg x kg(-1) and mivacurium 0.2 mg x kg(-1), anesthesia was maintained with isoflurane 0.6-1.6 minimum alveolar concentration and remifentanil 0.25 microg x kg(-1) x min(-1). Following complete recovery of neuromuscular blockade during induction, mivacurium infusion was initiated at 6 microg x kg(-1) x min(-1) in an adjusted dose to reflect adductor pollicis activity of 50, 75 or 100% of normal. The minimum stimulation thresholds obtained from each case were recorded.


RESULTS
Pre- and postoperatively, all 43 patients demonstrated clinically normal facial nerve function. In all cases, intraoperative facial nerve monitoring was performed successfully. There were no differences in threshold levels of the facial nerve stimulation between group I (1.84 +/- 0.4 mA ) and group II (1.97 +/- 0.2 mA). However, the stimulation thresholds of group III (1.53 +/- 0.4 mA ) were found to be lower than those of groups I and II (p < 0.05).


CONCLUSIONS
We conclude that partial neuromuscular blockade with mivacurium permits intraoperative facial nerve monitoring.
Cengiz
M
M
Department of Anesthesiology and Reanimation, Harran University, Medical School, Sanliurfa, Turkey. muscengiz@hotmail.com
Ganidagli
S
S
Alatas
N
N
San
I
I
Baysal
Z
Z
D000293:Adolescent; D000328:Adult; D000769:Anesthesia, Inhalation / Q000379:methods; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D004427:Ear Diseases / Q000601:surgery; D004558:Electric Stimulation / Q000379:methods; D005154:Facial Nerve / Q000187:drug effects / Q000502:physiology*; D020220:Facial Nerve Injuries / Q000517:prevention & control*; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007262:Infusions, Intravenous; D007530:Isoflurane / Q000008:administration & dosage; D007546:Isoquinolines / Q000008:administration & dosage*; D008297:Male; D008416:Mastoid / Q000601:surgery*; D008875:Middle Aged; D000077590:Mivacurium; D016343:Monitoring, Intraoperative / Q000379:methods*; D019148:Neuromuscular Blockade / Q000379:methods*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage; D013506:Otologic Surgical Procedures / Q000379:methods*; D010880:Piperidines / Q000008:administration & dosage; D000077208:Remifentanil; D016896:Treatment Outcome
D018685:Anesthetics, Inhalation; D006993:Hypnotics and Sedatives; D007546:Isoquinolines; D003473:Neuromuscular Nondepolarizing Agents; D010880:Piperidines; D000077590:Mivacurium; D007530:Isoflurane; D000077208:Remifentanil