Clinicopathological characteristics of incidental parathyroidectomy after total thyroidectomy: The effect on hypocalcemia. A retrospective cohort study.

BACKGROUND: The reported rate of incidental parathyroidectomy (IP) during total thyroidectomy varies between 6.4 and 31.1%. The aim of this study was to investigate the clinicopathological characteristics associated with IP.

MATERIALS AND METHODS: This is a retrospective cohort study which included 2556 patients who underwent total thyroidectomy between 2002 and 2012 at a single tertiary institution. Demographics, clinicopathological risk factors, and postoperative calcium levels were compared between IP and control group.

RESULTS: Incidental parathyroidectomy occurred in 18.3% of patients. IP patients had higher risk of postoperative biochemical (40.3% vs 17.3%, p < 0.001) and symptomatic hypocalcemia (14.3% vs 7.3%, p < 0.001) than no-IP group. Multivariate analysis showed malignancy, tumor size >10 mm, thyroid capsule invasion, extrathyroidal extension, lymph node metastases and central neck dissection, operation time, RLN injury, thyroid gland dimensions were independent risk factors for IP.

CONCLUSIONS: Our results indicate that patients with certain preoperative findings such as larger thyroid dimensions, diagnosis of malignancy and especially tumor >10 mm, extrathyroidal extension, and lymph node metastasis are at higher risk of IP and postoperative symptomatic hypocalcemia and these patients should be adequately informed and treated. Α meticulous intraoperative identification and the preservation of all parathyroid glands results in lower incidence of IP and postoperative hypocalcemia.