Reinnervation aspects of laryngeal transplantation

Although restoration of laryngeal function after laryngeal transplantation depends on appropriate reinnervation, non-selective reinnervation procedure s result in synkinesis and poor function restoration. This study was perfor med to test the feasibility of selective reinnervation procedures to restor e laryngeal function. Three surgical reinnervation procedures were studied each in a group of ten cats: in group 1 a non-selective procedure in which the recurrent laryngeal nerve (RLN) was cut and reanastomosed; in group 2 s elective abductor reinnervation was performed with the phrenic nerve; in gr oup 3 selective abductor reinnervation with the phrenic nerve (PN) was comb ined with selective adductor reinnervation with the ansa cervicalis. Ten we eks after surgical reinnervation abductor and reflex adductor functions wer e evaluated with videolaryngoscopy and electromyography. Findings demonstra ted that non-selective reinnervation not only gave poor abduction during in spiration but even resulted in paradoxical movement during reflex adduction . Selective abductor reinnervation resulted in good abductor function. Sele ctive adductor reinnervation with the ansa cervicalis brought about muscle tonus in the animals studied but no restoration of reflex adduction. Enhanc ed activity during respiratory distress gave only slight compromise to the abductor function. In all, selective laryngeal reinnervation with the PN an d ansa cervicalis produced good restoration of respiratory laryngeal functi on. However, deglutition following laryngeal motor and sensory reinnervatio n with protection of the respiratory tract is probably not sufficient, as i n the present group of animals no reflex glottic closure was achieved. More research is required.