Vocal fold paralysis may be an inadvertent result of several common surgeries, listed in the table. These include heart and lung operations, because the principal nerve of the vocal folds dips into the chest before returning to the larynx. Paralysis of the vocal fold is not necessarily a sign that the nerve has been cut. The nerve may also stop working if stretched or squeezed, and sometimes after surprisingly little handling. For this reason a vocal fold may be paralyzed after even the smoothest of operations. Finally, branches of the nerve may also be damaged by the breathing tube put in for general anesthesia.

In cases of paralysis in persons who have not had surgery that may damage the nerve, tumors are the most serious concern, with health consequences that reach far beyond voice. Radiologic studies that look over the entire path of the nerves to the larynx, including the chest, are essential. The consensus is that a CT (or CAT) scan of the neck and chest with contrast dye is the minimum study required to examine the nerves adequately. Lung cancers are the most common tumors to cause vocal fold paralysis.

In some 15-20% of cases, no reason is found for the vocal fold paralysis, even after appropriate radiologic studies. These are called idiopathic , and usually attributed to viral inflammation. It is important to understand that this is only an assumption.

Finding a cause for a paralyzed vocal fold can be simple, as in hoarseness that occurs immediately after a neck surgery, or very challenging. A meticulous history is the most important element in this search, aided by appropriate scans, which include the chest. A diagnosis of idiopathic vocal fold can only be made after all other possibilities have been eliminated.

In recent years, it has become clear that vocal folds may be only partially paralyzed. This is called “paresis” and, because the vocal fold retains some ability to move, can be especially challenging to diagnose. Vocal fold paresis is one of the most commonly overlooked diagnoses in laryngology.

Many otolaryngologists recommend waiting 6 months or a year to allow for vocal fold paralysis to clear up on its own before performing corrective surgery. This interval of time is determined largely by tradition – there is almost no evidence to support this practice. The appropriate interval should be determined individually in each case, based to extent of disability, likelihood of recovery and vocal demand.

Teflon™ was once commonly injected into the vocal folds for vocal fold paralysis. Teflon™ has been found to cause irritative growths called granulomas after a time, which usually have to be surgically removed. For this reason, it has been abandoned by most laryngologists. Any physician who proposes to use Teflon™ should explain clearly why it is preferable to another procedure.