Endocrine Abstracts

The aim of this study was to investigate: the incidence of postoperative paresis of the recurrent laryngeal nerve (RLN) and hypocalcemia; the frequency of incidental parathyroidectomy and the occurrence of hypocalcemia, and to find possible risk factors for hypocalcemia and RLN paresis.

Material and methods: Retrospective analysis of 550 patients after total thyroidectomy (TT) or completion thyroidectomy (CT) after histologically confirmed thyroid carcinoma. Postoperative RLN paresis was determined by postoperative laryngoscopy, and the index of recurrent injury (IRI) was calculated. Patients were monitored for postoperative clinical and biochemical hypocalcemia. Total calcium levels in plasma < 2.0 mmol/l were regarded as hypocalcemia. Incidental parathyroidectomy (IPT) was identified by histology.

Results: Postoperative unilateral RLN paresis occurred in 15 patients (2.7%), of which 4 cases were permanent (0.7%), and IRI was 8. Postoperative transient hypocalcemia was observed in 32 (5.8%) and permanent hypocalcemia in 2 patients (0.3%). The occurrence of RLN pareses and incidence of hypocalcemia was significantly higher in patients with malignant tumors than in benign lesions: 7.1% vs. 1.6% RR=4.47; 95% CI: 1.66–12.06; (P=0.004) and 9.8% vs. 4.8% RR =2.05; 95% CI: 1.00–4.12 (P=0.041), respectively. IPT was reported in 67 patients (12.2%). IPT/ non IPT and CT/TT patients had significantly higher incidence of transient hypocalcemia 13.4% vs. 5.2% RR=2.82; 95% CI 1.36–5.84 (P=0.015) and 27.3% vs. 5.8% RR=5.69; 95%CI: 1.58–20.48 (P=0.025), respectively.

Conclusion: Risk factors of transient hypocalcemia and unilateral RLN paresis were thyroid malignancies, extend of lymph node dissection, surgical technique and mainly the surgeon’s experience. Incidental parathyroidectomy and completion thyroidectomy significantly correlated with transient hypocalcemia. A higher frequency of incidental parathyroidectomy was observed in patients younger (≤45 years).