Following parotid surgery, what complication could potentially arise if the facial nerve is not preserved?

The preservation of the facial nerve during parotid surgery is crucial because this nerve is responsible for the motor control of facial muscles. If the facial nerve is not preserved during surgery, the most immediate and significant complication is paralysis of the affected side of the face. This paralysis results from the disruption of nerve signals that normally allow for movement of the facial muscles, leading to an inability to smile, frown, or make other facial expressions on that side.

Additionally, because the facial nerve has multiple branches that innervate different muscles, the specific muscles affected will depend on which branches are damaged. This can have profound implications for the patient's facial aesthetics, the ability to perform daily activities, and overall quality of life. Therefore, the preservation of the facial nerve is a primary concern during parotid procedures to prevent such functional impairments.