The goal of all of these various types of destructive surgery is similar to that following Botox – weaken or disable the affected muscles. They have only been used on a subtype of SD called adductor spasmodic dysphonia.
Thyroplasty is an operation where the vocal cords are moved further apart. That way, when the SD forces them closed, there is still a small space between the vocal folds. A review of this technique reported short term benefits with two-thirds of patients returning to baseline within one year. Denervation operations involve cutting the nerve(s) to the vocal cords. This produced a ‘hoarseness’ instead of SD but many patients have a return of their symptoms once the nerve regenerates. Selective Laryngeal Adductor Denervation-Rennervation (SLAD-R)is a type of denervation procedure but the cut nerves are attached to different, nearby nerves.
The original report from 1999, described 21 patients who were reported to do well although the outcome was a telephone survey and the opinion of an expert who clearly knew if the patients had received surgery or not. This raised the possibility of bias. Six patients had complications and four required additional surgery or therapy. No measure of the expected complication, voice breathiness, was provided.
A long-term, retrospective follow-up of some of the patients who had this procedure reported chronic breathiness in 30% and continued voice breaks in 26%. Unfortunately, this surgery has not become widely accepted and only one other center (Vancouver) has ever reported their experience with SLAD-R.