Gender Differences in Facial Paralysis Reanimation

Abstract

Sir:FigureFacial paralysis reanimation is influenced by several factors, of which denervation time and muscle atrophy are of high relevance. Thus, for paralysis of short duration (<6 months), cross-facial nerve grafting is recommended because it achieves a harmonious and synchronous smile with the nonparalyzed side, although contraction may be weak. For cases between 6 months and 2 years, in which cross-facial nerve grafting alone is not advisable because of the high risk of developing irreversible muscle atrophy while the axons reach the paralyzed side, Terzis introduced the “baby-sitter” procedure, with very good results.1 Finally, longstanding cases (i.e., >2 years) are best treated with muscle transfers. In our experience with treating facial paralysis, we have come to observe that gender also plays an important role in reanimation. We have seen that women defend better from injury and thus are more resistant than men to denervation and muscle atrophy. Several studies performed in animals have demonstrated that female subjects resist neural injury better and regenerate faster than male subjects.2,3 Sex hormones (i.e., progesterone) might be key in this phenomenon. These observations have led us to modify our standard protocol in facial paralysis reanimation and perform techniques indicated for palsy of short duration (i.e., cross-facial nerve grafting) in women with longstanding disease (facial paralysis for >3 years), achieving good functional and aesthetic results and a high grade of patient satisfaction. The case illustrated is a 28-year-old woman with a history of left facial paralysis secondary to resection of an acoustic neurinoma with whom we consulted for smile reanimation 4½ years later. Physical examination revealed complete facial paralysis with asymmetry at rest and on activity, lack of definition of the nasolabial fold, and no commissural excursion of the left side. A baby-sitter procedure with fibers from the right hemihypoglossal nerve with a nerve graft coapted to an ipsilateral zygomatic branch was performed together with cross-facial nerve grafting. On follow-up, the patient presented adequate excursion of the right commissure with acceptable symmetry in repose and smiling. The patient was very satisfied with the results obtained and refused to undergo connection of the cross-facial nerve graft (Fig. 1).Fig. 1: The patient shown had complete left facial paralysis secondary to resection of an acoustic neurinoma. Four and a half years later, a baby-sitter procedure was performed together with cross-facial nerve grafting. The patient was very satisfied with the results obtained from the first operation and refused to undergo connection of the cross-facial nerve graft. Preoperative views show the patient at rest (above, left) and while smiling (above, right). Two-year postoperative views show the patient in repose (below, left) and while smiling (below, right).Apart from resisting neural insult better, we have also observed that after reanimation with nerves other than the facial nerve (i.e., muscle transfer neurotized to the masseteric nerve), women develop brain plasticity to a greater extent than men. In our experience, most of (and only) our female patients reanimated with nerves other than the facial (masseteric nerve) learn to dissociate the movement of smile from the one that the donor nerve was originally serving. Elbert et al. have stated that brain plasticity develops in response to practice of behaviorally relevant actions.4 Furthermore, several studies have shown that women smile more than men in a wide variety of social circumstances.5 Thus, it is likely that the higher motivational drive of women toward smiling makes them more prone to develop cortical plasticity after reanimation. Finally, based on our clinical observations and the experimental data available, we believe that gender is an important factor to consider in the treatment algorithm of facial paralysis. Diego Marre, M.D. Bernardo Hontanilla, M.D., Ph.D. Department of Plastic and Reconstructive Surgery, Clinica Universidad de Navarra, Navarra, Spain DISCLOSURE There was no source of funds supporting this work. The authors have no financial interest in the methodology described. PATIENT CONSENT The patient provided written consent for the use of her images.