[Risk factors of hypoparathyroidism following total or near total thyroidectomy]

To study the risk factors for postoperative hypoparathyroidism or hypocalcemia.

Totally 414 patients with thyroid diseases who underwent total or near total thyroidectomy at Department of Head and Neck Surgery, Peking University Cancer Hospital and Institute from June 2007 to June 2014 were studied retrospectively. There were 119 male and 295 female patients with a median age of 47 years. The clinical and pathological features that related to post-operative hypoparathyroidism were studied by χ(2) test and multivariate Logistic regression analysis.

Of the 414 patients, 36.2% developed transient hypocalcemia, 36.5% developed transient hypoparathyroidism, 2.2% developed permanent hypoparathyroidism. In regression analysis, unilateral or bilateral center lymph node dissection were associated with mild transient hypocalcemia after surgery (OR=2.366, P=0.022; OR=5.216, P=0.000); unilateral or bilateral center lymph node dissection as well as surgical options were significant risk factors for severe transient hypocalcemia (OR=4.029, P=0.001; OR=8.384, P=0.000; OR=2.073, P=0.017) and hypoparathyroidism (OR=1.755, P=0.040; OR=4.144, P=0.000; OR=2.287, P=0.000). The parathyroid hormone concentration on postoperative day 1 was an independent risk factor for permanent hypoparathyroidism (OR=2.011, P=0.014). The concentration of parathyroid hormone threshold <5.28 ng/L was a predictor to permanent hypoparathyroidism with accuracy of 95.0%.

Bilateral center lymph node dissection is a risk factor of permanent hypoparathyroidism in patients received total thyroidectomy should be taken thoughtfully. The parathyroid hormone concentration on postoperative day 1 provides better prediction for persistent hypoparathyroidism.