Background: Hypoparathyroidism with hypocalcemia is the most frequent complication after thyroid surgery. Many risk factors have been involved in the development of this complication, with conflicting results. Incidental parathyroidectomy (IP) may be a frequent cause of postoperative hypocalcemia. In this study, we have evaluated the risk factors associated with the IP in a single-center cohort of patients undergoing thyroid surgery. Patients and methods: The incidence and the risk factors for IP were evaluated in 799 patients scheduled for surgical treatment for thyroid disease between January 2018 and December 2023. Parathyroid hormone levels and serum calcium levels, together with the histological specimens, were evaluated in all patients. Results: Post-operative temporary hypocalcemia was present in 239 (29.9%) patients. A total of 144 patients (21.9%) had an incidental parathyroidectomy. Younger patients (p = 0.014). Moreover, thyroid cancer (RR 1.4 (95 CI 1.114–1.882) OR 1.68 (95% CI 1.145–2.484), p p < 0.001) were strongly associated with the risk of incidental parathyroidectomy. Conclusions: Younger female patients with thyroid cancer and neck dissection were at the highest risk of incidental parathyroidectomy. A meticulous surgical dissection, together with imaging methods for the detection of the parathyroid glands, may reduce the incidence of this complication.
