Effectiveness of the “2 + 2” Parathyroid protection strategy in reducing permanent hypoparathyroidism after total thyroidectomy

To investigate current parathyroid management practices among thyroid surgeons in China and evaluate the clinical efficacy and safety of two parathyroid protection strategies—in-situ preservation versus the “2 + 2” approach (bilateral superior gland preservation with selective autotransplantation of bilateral inferior glands)—in patients undergoing total thyroidectomy (TT) with bilateral central lymph node dissection (BCLND). A national survey of 121 thyroid surgeons assessed preferences and factors influencing parathyroid preservation strategies. Additionally, a retrospective cohort of 1,099 patients with papillary thyroid carcinoma (PTC) who underwent initial TT+BCLND at West China Hospital between December 2017 and November 2023 was analyzed. Patients were divided into an in-situ preservation group and a “2 + 2” group. Outcomes included temporary hypoparathyroidism (THP), permanent hypoparathyroidism (PHP), postoperative parathyroid hormone (PTH), calcium (Ca), and 25-hydroxyvitamin D [25(OH)D] trends, surgical complications, and tumor recurrence. Multivariable logistic regression (standard for THP; Firth penalized for PHP) was performed to identify factors independently associated with each outcome. The survey revealed that 38.8% of surgeons preferred the “2 + 2” strategy in TT, with anatomical location and vascular supply as the main decision-making factors. In the clinical cohort, the “2 + 2” group showed a significantly lower incidence of PHP (1.4% vs. 3.7%, P = 0.020) but a higher rate of THP (68.7% vs. 45.4%, P < 0.01) compared to the preservation group. PTH and Ca recovery was faster in the “2 + 2” group during early follow-up. Postoperative complication and recurrence rates were comparable between groups. On multivariable analysis, the “2 + 2” strategy was independently associated with higher THP odds (aOR = 2.268, 95% CI 1.655–3.107, P < 0.001) but lower PHP odds (aOR = 0.324, 95% CI 0.131–0.801, P = 0.015); higher preoperative PTH was independently protective against both outcomes. The “2 + 2” strategy was associated with a lower risk of PHP after TT+BCLND, without compromising oncologic safety or increasing surgical complications, and may represent a reasonable alternative when inferior gland preservation is not feasible.