Effectiveness of preventative and other surgical measures on hypocalcemia following bilateral thyroid surgery: a systematic review and meta-analysis

A variety of measures have been proposed to reduce the incidence of post-thyroidectomy hypocalcemia. The aim of this study was to perform a systematic review and meta-analysis of preventive and other surgical measures on post-thyroidectomy hypocalcemia as reported in the literature.

Comprehensive searches of the PubMed, EMBASE, and Cochrane databases were performed, and the quality of included papers was assessed using the Cochrane risk of bias tool or a modified Newcastle-Ottawa Scale (NOS). The results of all included studies were summarized, and meta-analyses were performed where appropriate.

Thirty-nine randomized controlled trials (RCTs) and 37 observational studies were included. Measures studied included hemostatic techniques, extent of thyroidectomy and central neck dissection, surgical approach, calcium/vitamin D/thiazide diuretic supplements, parathyroid gland autotransplantation (PGAT) and intraoperative parathyroid gland (PG) identification, truncal ligation of inferior thyroid artery (ITA), preoperative magnesium infusion, and use of magnification loupes and Surgicel. Measures associated with significantly lower rates of transient hypocalcemia in meta-analysis were postoperative calcium and vitamin D supplementation compared to either calcium supplements alone (odds ratio (OR) 0.66; p=0.04) or no supplements (OR 0.34; p=0.007), and bilateral subtotal thyroidectomy (BST) compared to Hartley Dunhill (HD) procedure (OR 0.35; p=0.01). Meta-analyses did not demonstrate any measure to be significantly associated with a reduction in permanent hypocalcemia.

This review identified postoperative calcium and vitamin D supplementation and bilateral subtotal thyroidectomy (over HD) as being effective in prevention of transient hypocalcemia. However, the majority of RCTs were of low quality, primarily due to a lack of blinding. The wide variability in study design, definitions of hypocalcemia, and methods of assessment prevented meaningful summation of results for permanent hypocalcemia.