Recurrent laryngeal nerve palsy in thyroid gland surgery related to operations and nerves at risk.

Recurrent laryngeal nerve palsy is rare, but it is the most common complication in thyroid gland surgery. Depending on whether the measurement of the rate of occurrence is based on the number of operations or on the number of nerves at risk, the rate may vary widely. The elapsed time from the operation to when the palsy is considered permanent has also differed among various studies. In a ten-year series of 514 thyroid gland operations at a county hospital, all patients with a postoperative palsy were examined six months to ten years after the operation. After a primary operation almost 50% of the palsies were temporary, reducing the permanent palsy rate to 5.8% based on the number of operations, or 3.6% based on the number of nerves at risk. With more extensive surgery, the rate increased. This series illustrates the importance of the method by which the recurrent laryngeal nerve palsy rate is defined and calculated. The rates also show that the complication rate may be kept at a low level even in a nonspecialized unit.