Ultrasonic scalpel with knot tying protects parathyroid function for total thyroidectomy with central neck dissection

Hypoparathyroidism might be due to collateral thermal injury induced by harmonic scalpel (HS) after total thyroidectomy (TT) with central neck dissection (CND). The current study aimed to evaluate whether a clamp and tie (CAT) technique used to preserve parathyroid glands in situ could reduce damage to parathyroid function in HS patients undergoing TT plus unilateral or bilateral CND.

Medical records of 537 HS-operated patients with papillary thyroid carcinoma (PTC) undergoing TT plus unilateral or bilateral CND were retrospectively evaluated. Patients were divided into HS and HS-CAT groups based on whether the CAT techniques were used near parathyroid glands. Patients' characteristics such as age, sex, tumour size, operative time, pre- and post-operative levels of parathyroid hormone (PTH) and complications were analysed.

For patients undergoing TT plus unilateral CND, operative time was significantly shorter (P<0.001), but there were significantly higher incidences of transient hypoparathyroidism (P=0.002) on postoperative day 1 and incidental parathyroidectomy (P=0.036) in the HS group. There was no significant difference in permanent hypoparathyroidism. For patients undergoing TT plus bilateral CND, a significantly shorter operative time and sharper postoperative PTH decline was found in the HS group (P=0.029). However, there were no significant differences regarding incidences of incidental parathyroidectomy, transient or permanent hypoparathyroidism.

The CAT technique applied near parathyroid glands was a practical surgical application for decreasing the incidence of postoperative transient hypoparathyroidism for TT plus unilateral CND.