Truncal Ligation of the Inferior Thyroid Arteries does not Affect the Incidence of Hypocalcaemia after Thyroidectomy Mete Dolapc ¸ı, Mutlu Dog ˘anay, Erhan Reis, and Nuri Aydın Kama From the 4th Department of Surgery, Ankara Numune Hospital, Ankara, Turkey Eur J Surg 2000; 166: 286–288 ABSTRACT Objective: To assess the effect of truncal ligation of the inferior thyroid arteries during bilateral subtotal thyroidectomy on the incidence of hypocalcaemia after thyroidectomy. Design: Prospective non-randomised study. Setting: Teaching hospital, Turkey. Subjects: 216 patients who had bilateral subtotal thyroidectomy for non-toxic nodular goitre between 1990 and 1996. Interventions: The trunk of the each inferior thyroid artery was simply ligated during bilateral subtotal thyroidectomy. Main outcome measures: Clinical examination, and measurement of serum calcium, ionised calcium, and inorganic phosphate concentrations before and after operation. Results: Four patients (2%) had low concentrations of total and ionised calcium during the postoperative period. On physical examination three of them had spasms of the facial nerve, as seen in tetany. They were given calcium supplements orally and their laboratory results returned to reference ranges within 180 days. No patients developed permanent hypocalcaemia. Conclusion: Truncal ligation of the inferior thyroid arteries during bilateral subtotal thyroidectomy has no effect on the incidence of hypocalcaemia after thyroidectomy. Key words: thyroid surgery, post-thyroidectomy hypocalcemia. INTRODUCTION Hypocalcaemia after thyroidectomy is a rare complica- tion and mainly depends on the operation done and the underlying thyroid disease (13, 14). Permanent hypo- parathyroidism can occur in 1%–5% of patients after bilateral subtotal resection, and its incidence is higher after total thyroidectomy (8, 9). There are discrepan- cies among series regarding the incidence of transient symptomatic hypocalcaemia and rates of up to 20%– 83% have been reported by many investigators (14). It has been suggested that truncal ligation of the inferior thyroid arteries might be responsible for hypocalcae- mia after thyroidectomy but there is still controversy among this. We therefore organised a prospective study to assess the effect of truncal ligation of the inferior thyroid arteries during bilateral subtotal thyroidectomy on the incidence of hypocalcaemia after thyroidectomy. PATIENTS AND METHODS We studied 216 patients who required bilateral subtotal thyroidectomy for non-toxic nodular goitre in the 4 th Department of General Surgery, Ankara Numune Hospital between 1990 and 1996. To obtain a hom- ogeneous group, those having unilateral thyroidec- tomy, total thyroidectomy, or unilateral ligation of the inferior thyroid artery, were not included and only cases of bilateral subtotal thyroidectomy for non-toxic multinodular goitre were studied. During the study period 193 women and 23 men were operated on; their ages ranged from 13–75 years (mean 38). Bilateral subtotal thyroidectomy was done by a standard tech- nique; each superior thyroid vascular pedicle was divided between ligatures, and the trunk of each inferior thyroid artery was simply ligated. The poster- ior capsule of the lobes and the parathyroids were preserved in situ. On each side a 4–6 g remnant of thyroid tissue was left in place. In each patient, serum calcium, ionised calcium, and inorganic phosphate concentrations were measured before the operation and on the third postoperative day. The patients were also assessed for clinical signs and symptoms of hypocal- caemia during the postoperative period. The normal range of serum ionised calcium was 1.05–1.25 mmol/ L. Transient symptomatic hypocalcaemia was defined as a serum ionised calcium concentration of less than 1.05 mmol/L associated with symptoms that resolved with treatment within 180 days. Patients with perma- 2000 Taylor & Francis. ISSN 1102–4151 Eur J Surg 166 ORIGINAL ARTICLE