There are currently two purposes that I use selective denervation and reinnervation surgery for. I use it as a permanent treatment for adductor spasmodic dysphonia and I use it to reinnervate the anterior branch of the recurrent laryngeal nerve for vocal cord paresis or paralysis.
The nerve branch that I typically selectively cut, in order to denervate the larynx, is the anterior branch of the recurrent laryngeal nerve. This branch supplies first the lateral cricoarytenoid muscle and the more distal portion of it supplies the thyroarytenoid muscle. Together, these two muscles close the larynx. The lateral cricoarytenoid muscle rotates or adducts the vocal cord toward the midline, closing it for making sound, closing the vocal cord partway during breathing out (expiration) and closing the vocal cords during swallowing. The thyroarytenoid muscle tenses the vocal cord, which also aids in closing the vocal cords together as well as adjusting the pitch.
The donor nerve that I typically utilize to supply new nerve input is the omohyoid branch of the ansa cervicalis, although a lower branch can also be used if a longer length is needed. The omohyoid muscle typically contracts at the same time as the adductor muscles of the larynx and proves to be a good substitute for adductor nerve problems.
The denervation - reinnervation surgery was originally developed by Dr. Gerald Burke as a permanent surgical treatment for adductor spasmodic dysphonia. Nerve grafting seems to work equally well for inappropriate synkinetic reinnervation of the larynx where there is too much input into the adductor muscles on one side as well as persistent vocal paresis or paralysis where there is inadequate input into the adductor muscles on one side of the larynx.