The third surgery is CTA where the larynx is compressed causing the vocal folds to stretch. This locks you out of the lower range and isn't advised if you sing because it limits your range. The surgery requires an external incision and it normally requires a trachea shave to remove the additional bulge. Because it produces a limited amount of frequency shift, it tends to be recommended for people with a very low voice or smokers as it adds to the shift from VFS.