The Association of Discolored Parathyroid Glands and Hypoparathyroidism Following Total Thyroidectomy

Abstract

Background: It remains uncertain whether a parathyroid gland (PG) that appears darkened or severely bruised but still has an attached vascular pedicle should be left in situ or taken out and auto-transplanted following total thyroidectomy. Our study aimed to examine the impact of discolored PGs (DPGs) on short- and long-term hypoparathyroidism.

Methods: One hundred and three patients who underwent total thyroidectomy with 4 clearly identified PGs were analyzed. Location (superior/inferior) and color of each PG were recorded. Patients without DPG were grouped into I while those with 1-2 DPGs and ≥3 DPGs were grouped into II and III, respectively. Transient hypoparathyroidism meant adjusted Ca <2.00 mol/L 24 h after surgery and/or need for supplements. Protracted hypoparathyroidism meant a subnormal PTH at 4-6 weeks and/or supplements >6 weeks. Permanent hypoparathyroidism meant supplements ≥1 year.

Results: Relative to I, group III had greater adjusted Ca drop at postoperative 1-h (p = 0.012), 24-h (p < 0.001) and lower day-1 PTH (p = 0.015). Having ≥3 DPGs (OR 14.00, 95 % CI 1.575-124.474, p = 0.018) was an independent factor of transient hypoparathyroidism. However, permanent hypoparathyroidism rate was higher than in group I than II (p = 0.019). Eight patients (25.8 %) in group I had undetectable day-1 PTH, while none in group III had undetectable day-1 PTH. Graves' disease/toxic goiter (OR 15.166, 95 % CI 2.594-88.661, p = 0.003) and excised gland weight (OR 1.028, 95 % CI 1.010-1.046, p = 0.003) were independent factors of ≥3 DPGs.

Conclusions: PG discoloration is associated with transient hypoparathyroidism while normal colored PG with seemingly adequate blood supply does not always imply functionally normal gland. These findings highlights the need for a real-time intraoperative method to assess PG viability.