Electrical restoration of the blink reflex in experimentally induced facial paralysis

Unilateral facial paralysis is a relatively common problem encountered in clinical practice. Although the etiology of unilateral facial paralysis can be manifold, the resultant pathology is invariably the same. Unilateral facial paralysis is more than a physiologic and anatomic problem, it can be psychologically devastating. The irreversibly paralyzed face represents an extremely complex problem that cannot be satisfactorily corrected by any available technique at the present time. Ideally, one would achieve normal appearance at rest and symmetry for voluntary and involuntary movements. The most significant complication of facial paralysis is loss of the blink reflex, which may result in conjunctivitis, keratitis and, in extreme cases, loss of vision. None of the presently available surgical procedures can restore the involuntary blink. This study attempts to record the EMG activity of the nonparalyzed obicularis oculi muscle in the canine model and uses this electrical event to trigger a muscle stimulator resulting in contraction of the paralyzed obicularis oculi muscle. Our experiences have shown that it is feasible to restore a functionally symmetric blink in a unilaterally paralyzed obicularis oculi muscle by using the electrical activity of the opposite muscle as a trigger. This technique may also be applicable to the management of other unilaterally paralyzed facial muscles.