Facial nerve monitoring limitation

B. The monitoring result is unreliable until anaesthetic and equipment factors are excluded

Paralysis, electrode displacement, current settings and technical failure can abolish responses despite an intact nerve. Monitoring supplements, but does not replace, anatomical identification and surgical judgement.

Why every option is right or wrong

A. The facial nerve is definitely transected: Technical and pharmacological causes must be checked.

B. The monitoring result is unreliable until anaesthetic and equipment factors are excluded: Paralysis, electrode displacement, current settings and technical failure can abolish responses despite an intact nerve. Monitoring supplements, but does not replace, anatomical identification and surgical judgement.

C. Monitoring proves all branches are safe: An absent or present signal cannot guarantee anatomy or future function.

D. Increase dissection blindly until a response appears: This risks iatrogenic injury.

E. Ignore communication with anaesthesia: Neuromuscular blockade is directly relevant.

What if the scenario changed?

If a previously robust response was suddenly lost after traction with all technical factors corrected, nerve injury would be a serious concern.