Facial Nerve Disorders
A disorder in facial movement can have devastating effects on how a person interacts with other people. But did you know it can lead to trouble with eating, nasal breathing, and speech? It can even lead to blindness. The facial nerve and muscles serve very important functions in our very basic everyday functions. Muscle tone and movement in our cheeks and lips play a major role in moving food in our mouths and shaping sounds for speech. This same muscle function helps to keep our nostrils open for breathing. Perhaps most importantly our facial nerve and muscle function closes our eyelids, cleaning, lubricating and protecting our eyes.
Understanding the Different Facial Disorders
With regard to facial expression, our faces are largely how we are perceived by others. Although we have conscious control over facial expression, much of facial expression is mimetic and subconscious. We can consciously smile for a photograph, but when we are happy, we just smile without thinking about it. This mimetic function becomes important when discussing rehabilitation for facial nerve dysfunction.
Facial nerve dysfunction can be caused by a birth defect, trauma, infection, tumor or unknown causes. Initially, the cause of the dysfunction should be determined if possible. Any treatable conditions should be managed. The degree of dysfunction can be on a spectrum from complete paralysis to minor weakness and minimal facial expression asymmetry. Functional deficits such as speech/eating problems and incomplete eye closure are noted as well. Identifying the cause and degree of nerve dysfunction can give some guidance about prognosis for spontaneous recovery and direct rehabilitative efforts that might need only be temporary.
What to Expect
Rehabilitative efforts can be divided into different levels of the face. Beginning with eyelids that do not close completely, initial care might include lubricants and night time eyelid taping. The condition of the cornea must be followed by an ophthalmologist to ensure dryness is not causing eye damage. Temporary or permanent partial closure of the eyelids might be necessary. Blepharoplasty techniques can be done along with Gold/platinum weights, or springs can be inserted to close the upper lid. The lower lid can be tightened or stiffened with grafts. Adjacent jaw muscle or implant slings can also help to close the lids, the muscle offering the potential for movement beyond just static support. Drooping brows can be lifted, but the impact on lid closure has to be considered.
In the center of the face, the nostrils can partially collapse if neighboring muscles are weak leading to nasal stuffiness. This weakness can be improved with rhinoplasty maneuvers including stiffening grafts and supporting sutures. Midface lifting procedures can improve this as well as resting cheek asymmetry. Static slings of the patient’s tissue or artificial material can be used to help support sagging facial tissues.
A drooping corner of the mouth can be supported by adjacent jaw muscle or implant slings again with adjacent muscle offering the potential for some movement. A very droopy lower lip can be tightened with some tissue removal. Midface and full facelifts can also improve mouth symmetry. More advanced techniques can restore movement to the mouth, enabling a smile. These procedures are called dynamic facial reanimation – they restore active movement.
Repair of the nerve can be done if the two ends of the nerve are available, or replacement of the nerve can be performed with nerve grafts from nearby nerves or from the opposite side facial nerve if it is normal. These nerve transfers can successfully restore tone and movement when they are performed early – typically within one year of the injury. In cases of longstanding paralysis, where the muscles are no longer expected to work well, muscle is brought in from another part of the body with its own nerve and blood supply. Often some of the procedures mentioned previously are done together with nerve repair/replacement procedures because they usually work sooner. Some of the methods described require re learning how to activate the smile mechanism.
There are many variations in the presentation and management of facial nerve dysfunction. The needs of the patient have to be matched with the complexity of the rehabilitative effort. The facial plastic and reconstructive surgeon is uniquely trained and prepared to assist in managing this challenging problem.