Does exposing all parathyroids during total thyroidectomy with central lymph node dissection protect long-term function? A prospective cohort study

Hypoparathyroidism (HypoPT) is the most common complication after total thyroidectomy (TT) and central lymph node dissection (CLND) for thyroid carcinoma. However, there’s still no effective surgical strategy to prevent its incidence. This study evaluated the impact of sufficient intraoperative exposure of the parathyroid glands (PG) on postoperative parathyroid function, the rate of parathyroid autotransplantation, and incidental parathyroidectomy.

Prospective data from 133 consecutive patients who underwent TT and CLND by a single surgeon at the First Affiliated Hospital of Zhejiang University School of Medicine were systematically collected. All patients were categorized into sufficient exposure (exposed) group and insufficient exposure (control) group based on whether all 4 PGs were identified during surgery. PG exposure and autotransplantation were recorded intraoperatively, while incidental parathyroidectomy was determined via routine pathology reports. Postoperative parathyroid hormone (PTH) levels, serum calcium levels, and hypocalcemia-related symptoms (limb numbness/tetany) were monitored for at least six months. Continuous variables were compared using independent samples t-test for normally distributed data., while categorical variables were analyzed using Pearson’s chi-square test. A two-sided P-value < 0.05 was considered statistically significant.

No patients in the sufficient exposure group developed permanent hypoPT, while 2 patients in the insufficient exposure group exhibited biochemical hypoPT. Mean PTH levels were significantly higher in the sufficient exposure group (33.22 ± 16.48 pg/ml vs. 26.48 ± 10.94 pg/ml, P = 0.048) within six months. Parathyroid autotransplantation was more frequent in the sufficient exposure group (26.0% vs. 8.3%, P = 0.008). For transient hypoPT, incidental parathyroidectomy or clinical symptoms, there was no significant difference between groups (P > 0.05).

Sufficient exposure of the PGs during surgery can potentially protect parathyroid function in terms of PTH level without increasing transient hypoPT, indicating PG sufficient exposure is a practical way to protect parathyroid function.