Voice Abnormalities Prevalent After Thyroid Surgery

July 22, 2019

Researchers surveyed patients who underwent surgery for thyroid cancer and found a high number reported voice abnormalities post-operation.

More than 10% of patients who underwent surgery for differentiated thyroid cancer were identified as having an abnormal voice afterwards, suggesting a need for heightened awareness of voice abnormalities, according to a study published in JAMA Otolaryngology-Head & Neck Surgery.

“One of the more common adverse effects following thyroid surgery is a change in voice, which may be related to iatrogenic injury to the recurrent laryngeal nerve or superior laryngeal nerve during surgery or by direct cancer involvement,” wrote researchers led by Kevin J. Kovatch, MD, of University of Michigan, Ann Arbor. “However, vocal fold paralysis or paresis (vocal fold motion impairment [VFMI]) can occur even when the recurrent laryngeal nerve is left anatomically intact, and voice changes following surgery may be present even when no risk factors, surgical complications, or signs of VFMI are readily apparent.”

To assess voice outcomes further, Kovatch and colleagues conducted a cross-sectional population-based survey of 4,185 patients linked to the Surveillance, Epidemiology, and End Results (SEER) databases from sites in Georgia and Los Angeles. Patients had undergone surgery for thyroid cancer between January 2014 and December 2015 and were surveyed between February 2017 and October 2018.

Data were included for 2,325 respondents who met the inclusion criteria. Voice changes lasting more than 3 months were reported by a quarter of respondents (25.8%). About 12% of patients were identified as having abnormal voice on the Voice Handicap Index-10 (VHI-10) assessment; 4.7% reported VFMI diagnosed via laryngoscopy.

“Anticipated voice outcomes warrant consideration in the preoperative risk-benefit discussion, planned extent of surgery, and postoperative rehabilitation,” the researchers wrote.

Those patients who reported VFMI were more likely to have an abnormal VHI-10 score. A majority (60.5%) of respondents reporting VFMI had VHI-10 score greater than 11 compared with only 10.3% of patients without VFMI (P<.001). In contrast, only 21.9% of patients who had an abnormal voice on VHI-10 also reported VFMI diagnosis.

Multivariable analysis showed that being age 45 to 54 years (odds ratio [OR]=1.49), being black (OR=1.73) or Asian (OR=1.66), the presence of gastroesophageal reflux disease (OR=1.67), and having a lateral neck dissection (OR=1.99) were all factors associated with abnormal VHI-10 score.

“Based on earlier investigations on racial disparities in treatment of thyroid cancer and other cancers, the association between black and Asian race and VHI-10 scores greater than 11 is possibly secondary to less access to care, presentation and treatment at later stages, and/or treatment at low-volume institutions,” the researchers wrote. “Thus, based on past studies, it is possible that patients from minority racial and ethnic groups may be more likely to see low-volume thyroid surgeons and have more frequent complications, as higher complication rates among low-volume thyroid surgeons are well described.”

Beatriz Delgado Vargas, of Hospital Universitario De Torrejón, said although thyroid surgery is one of the most common surgical procedures worldwide, the comorbidities associated with it are often underestimated, most frequently vocal changes. 

"These changes are not taken into account when a patient is planned for surgery, and also there are subjective changes that are not measurable at the clinics and which frequency has been noted to be higher than expected," Delgado Vargas told Cancer Network.

In that sense, she said, the article is a well-conducted study in a large population.

"Therefore, it strengthens the fact that, even with a normal vocal fold motility, there are other factors that contribute to vocal changes, such as the scarring or perilaryngeal musculature disrupture that can occur after a more extensive surgery," Delgado Vargas said. "Other factors that have shown a positive association with vocal changes, such as the race, would need more studies to try to understand the etiology of them."