Interference between muscle relaxation and facial nerve monitoring during parotidectomy.
CONCLUSIONS
There is a worst case scenario involving a small risk of facial nerve injury and dysfunction of facial nerve monitoring. With regard to patient safety the use of a short-acting muscle relaxant and the analysis of neuromuscular blockade are necessary because these permit documentation of the temporal course of relaxation and the progress of surgery.


OBJECTIVE
The use of muscle relaxant may disturb facial nerve monitoring during parotidectomy. The aim of the study was to analyze the duration of muscle relaxation in relation to the progress of surgery.


METHODS
Twenty-one patients who underwent parotidectomy were enrolled in this prospective study, where the short-acting muscle relaxant mivacurium (0.2 mg/kg) was used. The neuromuscular blockade was monitored on the basis of train-of-four (TOF) peripheral stimulation. The time of intubation, skin incision, facial nerve identification and the end of surgery were documented.


RESULTS
The mean times of the TOF ratios (2/4; 3/4; 4/4), skin incision, and facial nerve identification differed significantly (chi(2)=0.05; df=1; p>0.05). For the earliest skin incision (21 min), 14.3% of patients have a TOF ratio smaller than 2/4 at which a neuromuscular block of the facial nerve is possible.
Thiede
Oliver
O
Department of Otorhinolaryngology, University Hospital Münster, Germany. schmael.hno@uni-muenster.de
Klüsener
Thorsten
T
Sielenkämper
Andreas
A
Van Aken
Hugo
H
Stoll
Wolfgang
W
Schmäl
Frank
F
D000328:Adult; D000368:Aged; D005154:Facial Nerve / Q000502:physiology*; D005260:Female; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D000077590:Mivacurium; D016343:Monitoring, Intraoperative; D009126:Muscle Relaxation / Q000187:drug effects*; D019148:Neuromuscular Blockade; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology; D013517:Otorhinolaryngologic Surgical Procedures / Q000379:methods*; D010306:Parotid Gland / Q000601:surgery*; D011446:Prospective Studies; D012449:Safety; D013997:Time Factors
D007546:Isoquinolines; D003473:Neuromuscular Nondepolarizing Agents; D000077590:Mivacurium