What is a primary reason for using a nerve stimulator during facial surgery?

Using a nerve stimulator during facial surgery serves the primary purpose of identifying critical nerves. This is crucial because the facial nerves control movements and functions of the face, and their preservation is vital to avoid complications such as facial paralysis or dysfunction. By applying a nerve stimulator, the surgical team can accurately locate and differentiate between the various branches of the facial nerve, allowing for safer surgical manipulation while maintaining nerve integrity.

The other options, while potentially relevant to different scenarios, do not specifically address the immediate need during facial surgery. Enhancing surgical visibility pertains to techniques or tools that improve the surgeon's view of the surgical field, while preventing excessive bleeding relates to hemostatic techniques or agents. Assisting in anesthesia may involve monitoring devices or techniques, but these are not the primary function of a nerve stimulator in this context.