Inadvertent parathyroidectomy risk factors in 1,373 thyroidectomies-male gender and presence of lymphadenopathy, but not size of gland, independently increase the risk.

Background: Inadvertent parathyroidectomy (IP) during thyroid operations is a recognised phenomenon. We evaluated the incidence of IP during thyroid operations in a large case-series and identified the risk factors involved. Methods: Retrospective review of all thyroidectomy operations [total thyroidectomies (TT) and near-total thyroidectomies (NTT)] performed in a single institution from January 2004 to January 2009. We excluded re-operative cases, combined thyroid and parathyroid pathology, hemithyroidectomies and neck lymph nodes (LN) dissections. Pathology reports were correlated with operative records to identify the details of the IP glands. Relevant data (patient demographic data, preoperative diagnosis and operative details) were collected and a logistic regression was performed. Results: One thousand three hundred and seventy-three patients were included in our study, 1,149 of them females (84%). IP rate was 11.3%. Univariate analysis showed that gender, thyroid gland weight, thyroid activity pre-operatively and type of operation are associated with IP. Logistic regression analysis has shown that female gender and the absence of LN in pathology were associated with less likelihood in developing IP than males and patients with presence of LN (P=0.051 and 0.014 respectively). IP occurs 2.14 and 2.28 times more often in TT and NTT when compared to the combination of TT and NTT (P=0.047 and 0.048 respectively). Conclusions: We present the largest single-centre case series on this topic, to our knowledge. The presence of LN, female gender and the type of operation are positively correlated to the IP rate. These factors could alert the surgeon to consider early calcium supplementation if the parathyroid glands (PG) have not been identified intraoperatively.