What is direct facial nerve repair?

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

Direct repair of the facial nerve is the best method for rehabilitating the paralyzed face. It provides a chance of restoring spontaneous emotional expression to the face. Restoring continuity of the nerve through coaptation of the 2 nerve ends is indicated whenever the available nerve length is sufficient to allow this to be accomplished without undue tension.

Primary nerve repair may be performed virtually anywhere along the course of the nerve. An exception is the most proximal part of the nerve in the cerebellopontine angle if the length is inadequate for grafting. In addition, if the nerve has been transected distal to the lateral canthus, repair is usually unnecessary, because the nerve typically regenerates spontaneously in the more medial areas of the face.

If the nerve repair is to be successful, functional motor units must be available to receive reinnervation. That is, the facial musculature must not have atrophied excessively, and the motor endplates must be functional without significant fibrosis that would prevent reinnervation.

There remains some controversy as to how long after injury these conditions may still be met. Most authors consider reinnervation by direct repair to be possible up to 1 year after the injury. Some, however, argue that less than or more than a year is reasonable. In selected cases, EMG may be helpful to determine whether the nerve and muscle can be stimulated distal to the site of injury. If stimulation is possible, a functioning motor endplate muscle unit is likely.

The optimal timing of repair has been discussed extensively in the literature. The commonly accepted belief today is that an injured nerve should be repaired as soon as possible, not in a delayed fashion. This belief was initially promoted in the 1970s on the basis of experimental data suggesting that repair ideally should be performed 3 weeks after injury. Subsequent data, however, reinforced the idea that the best long-term results are achieved when the repair is performed as soon as possible.


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