Supplementary Material for: Completion Thyroidectomy: Safer than Thought

Background: The aim of this study was to find out whether a substantial difference in terms of complication rates exists between primary and completion thyroidectomies following initial bilateral subtotal thyroidectomy in the light of current literature and our series. Patients and Methods: Total number of 696 patients who received completion thyroidectomy (Group 1, n = 289) and total thyroidectomy for differentiated thyroid cancer (Group 2, n = 407) and their data were reviewed and postoperative complications were compared between the groups and with the literature. Results: Transient and permanent hypocalcaemia rates were 20% and 5.8% in Group 1 and 10.5% and 5.1% for Group 2 respectively. Unilateral transient, bilateral transient and unilateral permanent recurrent laryngeal nerve palsy rates were 6.2%, 1.3% and 4.4% for patients in Group 1 whereas same complications were seen in 4.6%, 0.7% and 3.6% of patients in Group 2. When groups were compared for complications; temporary hypocalcaemia, unilateral temporary nerve palsy, and minor wound infection rates were statistically higher in Group 1, with no significant difference in permanent complications. Conclusion: When complication rates of re-operation after bilateral subtotal thyroidectomy and primary total thyroidectomy for differentiated thyroid cancer were compared in an unbiased fashion, completion thyroidectomy was shown to be as safe as a primary operation with regard to permanent complications