Background: Limited information exists about risk factors for postoperative hypoparathyroidism after bilateral thyroid surgery.
Methods: Between January 1 and December 31, 1998, bilateral thyroid surgery was performed on 5846 patients for benign and malignant thyroid disease. Data were prospectively collected by questionnaires from 45 hospitals. A logistic regression model was used to determine independent risk factors.
Results: The overall incidence of transient and permanent hypoparathyroidism was 7.3% and 1.5%, respectively. On logistic regression analysis, total thyroidectomy (odds ratio [OR], 4.7), female gender (OR, 1.9), Graves' disease (OR, 1.9), recurrent goiter (OR, 1.7), and bilateral central ligation of the inferior thyroid artery (OR, 1.7) constituted independent risk factors for transient hypoparathyroidism. When the multivariate analysis was confined to permanent hypoparathyroidism, total thyroidectomy (OR, 11.4), bilateral central (OR, 5.0) and peripheral (OR, 2.0) ligation of the inferior thyroid artery, identification and preservation of no or only a single parathyroid gland (OR, 4.1), and Graves' disease (OR, 2.4) emerged as independent risk factors.
Conclusions: Extent of resection and surgical technique had a greater impact on the rates of permanent postoperative hypoparathyroidism than thyroid pathologic condition. In bilateral thyroid surgery, peripheral ligation of the inferior thyroid artery at the thyroid capsule should be favored over central ligation, and at least 2 parathyroid glands should be identified and preserved. High-risk procedures, such as total thyroidectomy and Graves' disease, require special surgical training and expertise.