USA: Study on Hypocalcemia after Thyroidectomy

Reports on the rates of hypoparathyroidism or hypocalcemia after thyroidectomy vary widely. However, numerous studies have shown that identifying the glands alone is insufficient to improve hypocalcemia rates post-thyroidectomy.

A new study by Emmanuel A. Mannoh and the team has reported that Laser speckle contrast imaging (LSCI) is a promising technique and has the potential to help reduce the incidence of hypocalcemia after thyroidectomy as it provides surgeons with additional information during surgery to aid in the preservation of parathyroid function. This study is published in the Thyroid journal.

The objective of the study was to establish a speckle contrast threshold for classifying a parathyroid gland as adequately perfused and evaluate the relationship between intraoperative LSCI measurements and postoperative outcomes of total thyroidectomy patients.

The study included 72 thyroidectomy patients. After thyroid resection, an LSCI device was used to image all parathyroid glands identified, and a speckle contrast value was calculated for each. An average value was calculated for each patient, and the data were grouped according to whether the patient had normal (16–77 pg/mL) or low levels of parathyroid hormone (PTH) measured on postoperative day 1 (POD1).

Results of the Study

• A speckle contrast limit of 0.186 separated the normoparathyroid and hypoparathyroid groups with 87.5% sensitivity and 84.4% specificity. 7 of 8 patients with low PTH on POD1 had an average parathyroid speckle contrast above this limit.
• 54 of 64 patients with normal postoperative PTH had an average parathyroid speckle contrast below this limit. Taking this value as the threshold for adequate parathyroid perfusion, it was determined that only one vascularized gland was needed for normal postoperative parathyroid function.
• 64 of 69 patients (92.8%) with at least one vascularized gland (determined by LSCI) had normal postoperative PTH, while all 3 patients (100%) with no vascularized glands had low postoperative PTH.
• Overall, the rates of temporary and permanent hypoparathyroidism in this study were 8.3% and 1.4%, respectively.

Mannoh and team concluded that "LSCI is a promising technique for assessing parathyroid gland vascularity. It has the potential to help reduce the incidence of hypocalcemia after thyroidectomy by providing surgeons with additional information during surgery to aid in the preservation of parathyroid function."

Reference

Emmanuel A. Mannoh, Giju Thomas, Naira Baregamian, Sarah L. Rohde, Carmen C. Solórzano, and Anita Mahadevan-Jansen. Thyroid. Ahead of print. https://doi.org/10.1089/thy.2021.0093