Parathyroid autotransplantation into the brachioradialis protects parathyroid function during total thyroidectomy.

BACKGROUND: Surgery remains the foundation of differentiated thyroid cancer management. However, total thyroidectomy (TT) with lymph node dissection frequently predisposes patients to hypoparathyroidism (HypoPT). The sternocleidomastoid is the conventional site for parathyroid autotransplantation, but this approach cannot effectively assess graft viability and real-time functional monitoring. METHODS: Two sequential experiments were conducted. In Experiment 1, graft survival criteria were established by analyzing serum parathyroid hormone (PTH) ratios in the bilateral cephalic veins among 30 controls and 100 patients undergoing brachioradialis parathyroid autotransplantation. In Experiment 2, 180 TT patients undergoing bilateral central neck dissection were allocated into three groups (60 per group): in situ preservation, brachioradialis, or sternocleidomastoid autotransplantation. To address confounding, propensity score matching (PSM, 1:1:1) was performed, yielding 50 well-balanced patients per group. Temporary and permanent HypoPT, and validated graft survival were evaluated. RESULTS: In Experiment 1, bilateral PTH ratio ≤ 1.16 was defined as the physiological baseline, with ≥ 1.2-fold as the graft viability threshold, which showed superior 6-month survival vs the 1.5-fold standard (83% vs 74%, p < 0.05). Graft weight predicted survival (AUC = 0.654, cutoff = 28.5 mg). The brachioradialis group showed a significantly lower incidence of temporary postoperative HypoPT than the in situ preservation and sternocleidomastoid groups on day 1 and day 3, and than the in situ preservation group on week 1 (all p < 0.05). Permanent HypoPT rates were comparable across groups (p > 0.05). Under the 1.2-fold criterion, brachioradialis graft survival rates were significantly higher than those at 1.5-fold criterion on day 1, 3 and week 1 (all p < 0.05). These findings were confirmed by PSM analysis. CONCLUSIONS: Brachioradialis parathyroid autotransplantation is safe and effective, while significantly reducing the risk of early postoperative HypoPT. Brachioradialis autotransplantation were recommended for compromised or inadvertently excised parathyroid glands. CLINICAL TRIAL REGISTRATION: https://www.chictr.org.cn/bin/home, identifier ChiCTR2400080970.