Risks of Hypoparathyroidism After Total Thyroidectomy in Children: A 21-Year Experience in a High-Volume Cancer Center

Background Hypoparathyroidism occurs relatively frequently after thyroid surgery in children. However, few studies have reported risk factors. We aimed to identify risk factors for hypoparathyroidism that occurred after total thyroidectomy for proven or suspected malignancy in children. Methods Children (aged <= 18 years) who underwent total thyroidectomy for neoplasm or RET germline mutation at our institution between 1997 and 2018 were included. We retrospectively reviewed demographics, surgical indications, perioperative and follow-up laboratory results, pathologic results, and duration of calcium/calcitriol supplementation. Risk factors for hypoparathyroidism were identified by multivariate analysis. Results Of 184 consecutive patients, 111 had undergone surgery for neoplasm; these diseases were primarily malignancies (106, 95.5%), predominantly papillary carcinoma (103, 92.8%). The remaining 73 patients had undergone early thyroidectomy for RET germline mutation. Among all patients, 67 (36.4%) had hypoparathyroidism: 61 transient and 6 permanent. In a multivariate analysis, central neck dissection (odds ratio 4.3, 95% confidence interval 2.0-9.1) and gross extrathyroidal extension (odds ratio 4.9, 95% confidence interval 2.0-12.1) predicted overall hypoparathyroidism; however, no significant factors were associated with permanent hypoparathyroidism. Most patients with permanent hypoparathyroidism (5 of 6) had undergone therapeutic central neck dissection. When central neck dissection was performed, younger children had a higher risk of overall hypoparathyroidism. Conclusions In pediatric total thyroidectomies, central neck dissection and gross extrathyroidal extension were major predictors for overall hypoparathyroidism. Surgeons performing thyroidectomy in such patients should be aware of the relatively high risk, preserve parathyroid tissue to the extent possible, and be conscientious regarding postoperative calcium monitoring and replacement.