Laryngeal physiology and voice acoustics are maintained after minimally invasive parathyroidectomy

This prospective single-arm study investigated both laryngeal physiology and voice acoustic measures in patients undergoing minimally invasive parathyroidectomy (MIP) due to primary hyperparathyroidism (primary HPTH).

Avoidance of recurrent or superior laryngeal nerve injury and maintenance of normal laryngeal physiology and vocal function are key goals in the treatment of primary HPTH. No data are available comparing pre- and postoperative MIP laryngeal physiology and voice acoustics.

Patients served as their own controls and underwent identical pre- and postoperative assessment. True vocal fold mobility was assessed and recorded using transnasal fiber-optic laryngoscopy. Vocal capacity was recorded with maximum phonation time and vocal stability by frequency-based voice measures, that is, mean fundamental frequency (F0), standard deviation of the fundamental frequency (F0SD), and jitter and shimmer as measured by relative average perturbation and mean shimmer in decibels, respectively.

A total of 104 patients were enrolled [26 men, mean age = 53 years, range 29-79 years; 78 women, mean age = 56 years, range 16-83 years). All completed the protocol and were analyzed according to intent to treat. MIP was accomplished in 95 patients, and 9 were converted to general anesthesia. The cure rate was 100%, as evidenced by normalization of serum calcium levels. Both real-time agreement and blinded inter- and intrarater reliability testing for laryngeal physiology ratings were 100%. One patient (<1%) exhibited a recurrent laryngeal nerve injury. No significant differences (P > 0.05) were found for any voice acoustic parameter between pre- and postoperative MIP (ie, maximum phonation time, F0, F0SD, relative average perturbation, or shimmer in decibels).

MIP can be performed with exquisite disease control and without significant effects on laryngeal physiology or voice acoustic measures. For the first time, both physiologic and acoustic data support the use of MIP.