Endocrine Abstracts

Background: The surgical technique and the extent of thyroidectomy are related to parathyroid injury and hypoparathyroidism.

Methods and results: We retrospectively analyzed the files of 552 patients who underwent thyroidectomy in our surgery department between 2015-2017 with the aim to assess the incidence and impact of intraoperative features that may predispose to postoperative hypoparathyroidism (PoSH).

Results: 171 (30.97%) patients, 153 women (89.5%), median (IQR) age 49(22) years developed PoSH (88.37% transient). The intraoperative features studied in these PoSH patients were: cervical neck dissection and lymphadenectomy (15.2%), surgeon reported difficult thyroidectomy (8.3%), the presence of retrosternal goiter (7%), no parathyroid gland identification (6.8%) and re- operative thyroid surgery (2.3%). Median age was higher in PoSH patients with surgeon reported difficult thyroidectomy [62(7.5) vs 48 (22.75) years, P = 0 .007]. Surprisingly, median postoperative calcemia was higher in patients with reported difficult surgery [8.2(0.2) vs. 7.9(0.6) mg/dl, P = 0 .043]. Although patients with no intraoperative parathyroid gland identification had a higher prevalence of inadvertent excision of parathyroid tissue (20% vs 2.2%, P = 0 .037), the median postoperative serum calcium level was higher in these patients [8.25 (0.25) vs. 7.9 (0.67) mg/dl, P = 0 .001]. Our data showed that when cervical neck dissection and lymphadenectomy was necessary it was associated with a higher median surgery duration [152 (70) vs. 127 (53) min, P = 0 .007] and a higher median serum calcium decrease [1.8 (0.85) vs. 1.6 (0.67) mg/dl, P = 0 .048]. Postoperative and long-term biological parameters (calcemia, PTH, 25-hydroxyvitamine D, phosphatemia) were similar in PoSH patients regardless the presence of retrosternal goiter or the need for re- operative thyroid surgery.

Conclusions: Our data, that needs further validation in large trials, showed that in PoSH patients intaoperative features, of which in particular cervical neck dissection and lymphadenectomy, must be carefully monitored.