A team led by researchers at the Kobe University Graduate School of Medicine conducted the study, “Quality of voice after surgical treatment for thyroid cancer.” It was published online ahead of print in December 2012 in the journal Thyroid.
The study authors state that hoarseness caused by paralysis of the recurrent nerve in patients who have had surgery for thyroid cancer is a common and well-studied side effect. However, they argue that voice quality in patients who have clinically intact recurrent nerves following thyroidectomy has not been fully explored.
The researchers looked at data on 110 patients who had surgeries for thyroid cancer. They looked at several vocal parameters, including patients voice handicap index-10, fundamental frequency, voice jitter, and average air flow rate. In all of the patients, it was confirmed that the recurrent nerves had not sustained apparent injury, and that there was mobility of the vocal cords.
The results of the study showed that immediately after the surgical procedures, there were significant decreases in voice quality. For example, there were increases in jitter and shimmer in the voices of the study participants. However, the researchers also found that these effects appeared to gradually decrease over time, and they lost significance a month following the surgery.
The study authors conclude that their results demonstrate that surgery for thyroid cancer does impact the quality of voice. This may be due to disruption or manipulation around recurrent nerves, even if these nerves are still intact. However, these effects are often temporary and disappear over the course of the month following the procedure.