Surgical complexity and early post-operative parathyroid function following incidental parathyroidectomy during thyroidectomy

Objective: This study evaluated whether surgical complexity influences post-operative parathyroid function in patients with IP. Methods: A retrospective cohort study was conducted including 371 patients who underwent thyroidectomy between 2017 and 2020. Seventy-two patients (19.4%) with histologically confirmed IP were classified into total thyroidectomy, completion thyroidectomy, and substernal thyroidectomy groups. Post-operative day-1 parathyroid hormone (PTH) level was the primary outcome. Secondary outcomes included calcium levels and biochemical hypocalcemia. Results: IP was identified in 72 patients (19.4%). The number of excised parathyroid glands and autotransplantation rates were similar among groups. Patients undergoing substernal thyroidectomy had the lowest post-operative day-1 PTH levels (13.9 pg/mL), whereas the highest levels were observed after completion thyroidectomy (24.8 pg/mL). Although differences in post-operative PTH and calcium levels were not statistically significant, lower post-operative parathyroid function was observed with increasing surgical complexity. Biochemical hypocalcemia occurred in 84.6% of substernal thyroidectomy patients compared with 72.3% and 41.7% of total and completion thyroidectomy patients, respectively (p = 0.051). Conclusions: Surgical complexity may adversely affect early post-operative parathyroid function after IP.