Evaluation of risk factors for incidental parathyroidectomy during thyroidectomy

Objective: Hypocalcemia remains a common problem after thyroidectomy. One of the most common causes of this condition is incidental parathyroidectomy. This study aimed to evaluate the risk factors for incidental parathyroidectomy and the clinical outcomes of incidental parathyroidectomy in patients undergoing thyroidectomy. Methods: A retrospective analysis was conducted on 817 patients who underwent thyroidectomy at the Department of General Surgery at Gazi University between January 2015 and June 2022. Medical records were reviewed for demographic, pathological, and clinical variables. The primary outcome measure was the factors affecting incidental parathyroidectomy, and the secondary outcome measure was the clinical results of incidental parathyroidectomy. Results: Adding lymph node dissection to thyroidectomy statistically increased the frequency of incidental parathyroidectomy (p<0.001). The incidence of incidental parathyroidectomy was significantly higher in patients whose final diagnosis was malignant (p=0.006). Considering some characteristics of the malignant group, extrathyroidal spread, lymphatic invasion, vascular invasion, and positive surgical margins were not statistically significant for incidental parathyroidectomy. Post-operative calcium levels were statistically significantly lower in the incidental parathyroidectomy group (p<0.001). The incidental parathyroidectomy group had a significantly higher incidence of post-operative biochemical hypocalcemia (calcium level <8.5 mg/dL) (p<0.001). Conclusion: Incidental parathyroidectomy may occur during total thyroidectomies. This situation increases with thyroidectomies performed for malignant reasons and lymph node dissection. Moreover, although incidental parathyroidectomy causes post-operative biochemical hypocalcemia, its effect on symptomatic hypocalcemia is low.