The Incidence of Hypoparathyroid Tetany After Thyroid Operations: Relationship to Age, Extent of Resection and Surgical Experience

In a series of 2,513 thyroid operations performed at the Royal Brisbane Hospital between July 1, 1944, and June 30, 1964, postoperative tetany occurred in 19 cases (0·76%). The incidence was significantly higher in younger patients, after more extensive resections and with less experienced surgeons. One or more of these adverse factors was present in every case, the last being most common. The data were insufficient to confirm or exclude a relationship to the sex of the patient, the type of thyroid disease, or the type of preoperative medical treatment. During the period reviewed, the average number of operations per year fell from 161 to 63, the average number of operations per surgeon per year fell from 18 to five, and the expected percentage of patients operated on by adequately experienced surgeons fell from 80 to 30. In the five years ending June 30, 1969, the incidence of postoperative tetany was 3·8%, a fivefold increase compared with the preceding 20 years, and it is suggested that this reflected the lesser experience of thyroid surgery of present-day surgeons compared with those of 20 years ago. The only satisfactory way of reversing this trend would be by an agreement amongst surgeons to reduce the number who regularly undertake thyroid surgery in proportion to the reduced number of operations needed. The incidence of postoperative tetany would also be reduced if radical resection for hyperthyroidism was discontinued, and If surgery was avoided in patients aged under 30 years except after failure of medical treatment.