When is facial nerve repair indicated?

Updated: Nov 28, 2018
  • Author: Tang Ho, MD, MSc; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Facial nerve repair is an option for cases of facial paralysis in which there is no reasonable likelihood of spontaneous return of function. Essential in determining whether repair is indicated are the cause of the paralysis and the duration of time since the injury. In this regard, some general principles will be helpful.

In general, transected nerves produce the best result when reapproximated. This produces an intact motor nerve supply from the facial motor nucleus in the pons to the muscle endpoint and is preferable whenever possible. If direct repair without tension is possible, it should be performed. Otherwise, a cable graft may be inserted to produce a tensionless coaptation of the proximal nerve stump to the distal branch or branches. Nerve crossover techniques are used when the proximal nerve stump is inadequate or inaccessible and cannot be used for grafting.

Another simple rule of thumb is that the sooner an injured facial nerve can be repaired, the better the long-term result. Once regarded as somewhat controversial, this rule is now believed to hold true for most cases.

In cases of trauma where the continuity of the nerve is in question, exploring within the first 3 days after injury is extremely desirable. Within this timeframe, the surgeon can use a nerve stimulator intraoperatively to identify the branches of the facial nerve. Once degeneration has occurred, stimulation of the nerve is not possible, and identifying the branches in an inflamed field can be extremely difficult.

Fibrosis of the nerve, fibrosis of the motor endplate, and atrophy of the muscle all ensue after injury. The surgeon is in a race against this inevitable process. Thus, a repair performed 18 months after the onset of paralysis is sure to have a poorer chance of success than a repair performed in the first month after injury.

Waiting may be appropriate in specific instances, depending on the health of the patient, oncologic surveillance issues, and other concerns. Nonetheless, when possible, maximizing the patients’ chance of a satisfactory outcome is desirable. In such cases, it is worthwhile to consider alternatives to facial nerve repair, such as facial reanimation procedures.

In addition, patient-specific factors influence clinical decision-making. In an elderly patient, slower nerve regeneration is expected, and the result of repair is likely to be poorer than could be achieved in a younger patient. If the patient’s life expectancy is short, one may elect to perform an adjunctive procedure that produces an immediate improvement (eg, a dynamic muscle sling) rather than a nerve repair that, even in the best of circumstances, takes some time to yield results.


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