[Reinnervation of the posterior cricoarytenoid muscle by the phrenic nerve for bilateral vocal cord paralysis in humans].

OBJECTIVE

To reestablish the respiratory abduction of the paralyzed vocal cord through reinnervation of the posterior cricoarytenoid(PCA) muscle by the phrenic nerve in humans.

METHODS

In six cases with bilateral recurrent laryngeal nerve paralysis, the phrenic nerve was anastomosed to the anterior branch of recurrent laryngeal nerve, while the adductor branch of recurrent laryngeal nerve was severed and its proximal end was implanted into the PCA muscle belly in one side, for the other side nerve-muscle pedicle technique was used. All cases had been subjected to preoperative and postoperative video laryngoscopy, stroboscopy, electromyography, voice recording and acoustic analysis.

RESULTS

Among the 6 patients, it is observed in five cases' phrenic nerve reinnervation side the inspiratory abducent motion evidently recovered, and the abducent range was from 3 to 5 mm, While only slight abductent motion or no motion could be recorded on the other side reinnervated with nerve-muscle pedicle technique, and the vocal cord excursion on this side was less than 1 mm in all cases. It is because the glottis is broad enough for the patients to have daily activities without short of breath, so all of them were decannulated postoperatively. The reinnervated PCA muscle by the phrenic nerve showed typical inspiratory high frequency discharge with 100-200 ms delay as compared with the other side, indicating the phrenic motoneuron pattern. No long-term diaphragmatic paralysis and lesion of respiratory function was found. All cases' voice was not weakened, and no aspiration occurred.

CONCLUSION

The phrenic reinnervation is feasible clinically for treating vocal cord paralysis, and it is found to be more effective for restoring inspiratory abducent function than the nerve-muscle pedicle technique.