Postoperative hypoparathyroidism after completion thyroidectomy for well-differentiated thyroid cancer

Thyroid surgery may lead to postoperative complications. The aim of this paper was to determine whether the rate of postoperative hypoparathyroidism (HPT) is influenced by whether surgery is staged.

Single-institution retrospective observational study.

The clinical records of 786 patients treated at the Otolaryngology Unit of the Azienda USL-IRCCS di Reggio Emilia between January 1990 and December 2015 were reviewed. Patients were divided into two groups according to the surgical treatment received: group TT (637 patients, 81.04%) underwent single-stage total thyroidectomy; Group cT (149 patients, 18.96%) underwent loboisthmusectomy and delayed completion total thyroidectomy. Transient and permanent HPT, assessed after 6 months of follow-up, were the primary endpoints. Risk factors of postoperative HPT were also analysed as secondary outcomes.

Rates of transient HPT in group TT were higher than those observed in group cT, (P = 0.0057). Analysis of risk factors identified sex as an independent risk factor for transient HPT only for group TT (P = 0.0012) and the number of parathyroid glands remaining in situ (PGRIS) as an independent risk factor for transient and permanent HPT for group TT (P < 0.0001 and P = 0.0002, respectively).

This study suggests that the risk of transient postoperative HPT is lower in patients that undergo completion thyroidectomy. Further independent risk factors for postoperative HPT are female sex and PGRIS score. In light of the growing use of conservative surgery for thyroid neoplasms, these findings could help to adequately plan surgery in order to reduce endocrine complications.