# Intraoperative Management of Parathyroid Glands and Long-Term Outcome of Parathyroid Function Following Total Thyroidectomy

## TL;DR

This study shows that preserving at least one viable parathyroid gland during thyroid surgery significantly reduces the risk of long-term parathyroid dysfunction.

## Contribution

The study introduces the stabbing test as a practical intraoperative method to assess parathyroid viability and improve long-term outcomes.

## Key findings

- Preserving at least one viable parathyroid gland in situ reduces the PHPS rate to 0.2%.
- The stabbing test effectively identifies viable parathyroid glands based on blood oozing.
- Only 0.95% of patients experienced permanent hypoparathyroidism after 12 months.

## Abstract

Background/Objectives: In situ preservation is the primary strategy to preserve parathyroid gland (PG) function during thyroid surgery, while autotransplantation is used when inadvertent removal or devascularization occurs. Deciding on the optimal approach intraoperatively for exposed PGs remains challenging. This study evaluates intraoperative PG management strategies and long-term outcomes of PG function following total thyroidectomy. Methods: This retrospective study included 543 patients undergoing primary total thyroidectomy, excluding those with comorbid parathyroid disease. A stabbing test assessed the vascular supply of exposed PGs. PGs with fresh blood oozing after the test were preserved in situ; otherwise, they were autotransplanted. Intact parathyroid hormone (iPTH) and ionized calcium (iCa) were measured preoperatively and on postoperative day 1 (PO-1D), and during follow-up. Permanent hypoparathyroidism (PHPS) was defined as iPTH < 15 pg/mL, iCa < 4.2 mg/dL, or continued need for calcitriol or calcium supplementation after a postoperative period of 12 months (PO-12M). The PHPS rate was compared with the corresponding intraoperative PG status. Results: A total of 528 patients were enrolled in this study. At PO-1D, 434 patients (82.2%) had iPTH ≥ 15 pg/mL, 65 (12.3%) had iPTH between 4 and 15 pg/mL, and 29 (5.5%) had iPTH < 4 pg/mL. At PO-12M, 527 patients (99.81%) had iPTH ≥ 15 pg/mL, 1 (0.19%) had iPTH between 4 and 15 pg/mL, and none had iPTH < 4 pg/mL. Five patients (0.95%) were in PHPS after PO-12M. Among the 462 patients with at least one viable PG preserved in situ, the PHPS rate was 0.2%, compared to 6.1% (66 patients) for those without a viable PG preserved in situ (p < 0.001). Conclusions: Permanent hypoparathyroidism is rare when at least one viable PG is preserved in situ during total thyroidectomy. The stabbing test is a simple, useful, and cost-effective method to assess the vascular supply of exposed PGs, providing surgeons with essential information for intraoperative PG management.