Column 7. What Is the Acceptable Incidence for Persistent Recurrent Laryngeal Nerve Paralysis and Persistent Hypoparathyroidism as Complications of Thyroid Surgery

The incidences of recurrent laryngeal nerve paralysis and hypoparathyroidism vary according to the extent of surgery and whether node dissection is performed. They are also influenced by whether it is primary surgery or repeat surgery. Persistent recurrent laryngeal nerve paralysis was reported to occur in 0.1–0.9% of patients who underwent surgery for benign nodules, indicating that less than 1% is desirable [1–3]. However, the incidence was reported to be 0.5–3.5% of surgery cases with thyroid carcinoma [4–8]. It is speculated that the variability in incidence is due to the variation in the grade of severity of the cases and the variation in the extent of surgery between institutions. The incidence of persistent recurrent laryngeal nerve paralysis ranged from 0.4% to 1.8% for thyroid surgery, including that for benign and malignant diseases, indicating that less than 2% is desirable for thyroid surgery as a whole [9–11]. There are many publications that have not concretely described how the larynx was observed and it is possible that the actual incidence is higher than indicated above.