Masseter to facial nerve transfer
The optimal reconstruction of an injured facial nerve would be reinnervation of the paralyzed facial muscles by ipsilateral nerve repair. However, in most instances of facial paralysis, the proximal ipsilateral nerve stump is not available for primary repair or grafting. The lingual, hypoglossal, spinal accessory, phrenic, and ansa cervicalis have been transferred to the distal facial nerve, with variable degrees of success in restoring the tonicity of the facial muscles.
Treatment of facial paralysis
Currently, the most utilized nerve transfer is hypoglossal-facial; this procedure has proven its reliability. But the tradeoffs such as hemilingual atrophy, facial hypertonia, and facial synkinesis are difficult to manage, and this has encouraged the search for a better solution for facial paralysis. Several variations have been described to avoid the side effects: partial nerve transfer, jump interpositional graft anastomosis, and end-to-side neurorrhaphy, among others.
In contrast to experimental models in animals, the functional motor recovery following end-to-side neurorrhaphy is not precisely predictable in humans. Zuker and Manktelow described the motor branch of the fifth nerve as a source of axons to innervate a transplanted gracilis muscle in patients with Moebius syndrome, where the hypoglossal nerve is frequently involved to some extent. in 2004 we published the first report of masseter to facial nerve transfer for facial reanimation (Journal of Reconstructive Microsurgery, Volume 20, Number 1, 2004) in patients with early facial pralysis (less than 18 months) , it has become the ideal treatment for those patients in my practice.
This nerve transfer has several
advantages: 1) there is no morbidity related to the donor nerve; 2) the complete procedure can be easily performed by the standard preauricular incision used in a face lift; and 3) because of the proximity of the main branches of the facial nerve to the masseteric nerve, the transfer can be selectively used in patients with partial lesions of the facial nerve or to avoid facial synkinesis.
Tratamiento de la paralisis facial
El tratamiento optimo de la paralisis facial es reinervar los musculos paralizados con axones provenientes de nervo facial del mismo lado. Sin embargo a mayoria de casos sucptibles de tratamiento quirurgico el cabo proximal no se encuentra disponible. para reparacion priaria. o para puentes nerviosos. Los axones de otros nervios como el lingual, hipogloso, accesorio espinal o el asa cervical han sido utilizados para reinervar los musculos parlizados con un grado variable de exito. El mas frecuentemente utilizado ha sido la transferencia hipogloso facial pero tiene varios efectos colaterales como la hemiatrofia lingual, la hipertonia facial y las disquinesias faciales.
Zuker y Mankenlow describieron la rama motora del masetero para inervar el musculo gracilis transferido en pacientes con sindrome de Moebius. Nosotroa fuimos los primeros en describir la transferencia massetero facial para la reamimacion de la cara paralizada. (Journal of Reconstructive Microsurgery, Volume 20, Number 1, 2004) este metodo se ha convertido en el metodo ideal de tratamiento para mis pacientes con paralisis facial temprana (de menos de 18 meses de evoucion) .
Este tratamiento tiene varias ventajas: 1) no hay morbilidad relacionada con e sitio donante, 2) el procedimiento completo se realiza a travez de una incision de ritidopastia y 3) debido a la proximidad entre los dos nervios se puede decidir a que rama del facial se anastomosa el nervio massetero avitando los movimientos en masa y disquiesias muy marcadas.
