Rate of drop in serum calcium as a predictor of hypocalcemic symptoms post total thyroidectomy

The Rate of Postoperative Decline in Parathyroid Hormone Levels Can Predict Symptomatic Hypocalcemia Following Thyroid Cancer Surgery with Neck Lymph Node Dissection

OBJECTIVE

Identifying early predictive indicators of symptomatic hypocalcemia in patients after thyroidectomy with neck lymph node dissection can help to identify high-risk patients, provide timely intervention, and improve prognosis.

METHODS

A retrospective analysis of all relevant information was conducted for patients who underwent total thyroidectomy with neck lymph node dissection at our hospital between April 2021 and September 2022. The primary outcome measure was symptomatic hypocalcemia.

RESULTS

Of the 210 patients who underwent total thyroidectomy with l neck lymph node dissection, 76 patients (36%) experienced symptoms of hypocalcemia. The analysis confirmed that the rate of parathyroid hormone (PTH) decline (OR = 238.414, 95%CI: 51.904-1095.114, P = 0.000) was an independent risk factor for symptomatic hypocalcemia after total thyroidectomy with neck lymph node dissection. The ROC curve indicated that a PTH decline cutoff value of 0.7425 was significantly correlated with symptoms of hypocalcemia, with a sensitivity of 89% and specificity of 69%, which could effectively predict symptomatic hypocalcemia.

CONCLUSION

A PTH decline rate greater than the cutoff value of 0.7425 is a predictive factor for symptomatic hypocalcemia in adults and may be considered as a high-risk patient and actively managed to supplement calcium as soon as possible to ensure patient safety.

Re-do Operation Using a Robotic System due to Locoregional Recurrence after Initial Thyroidectomy for Thyroid Cancer

Locoregional recurrent thyroid cancer is commonly treated with re-do operation. This study aimed to investigate the feasibility of using robotic system for re-do operation in locoregional recurrent thyroid cancer. Sixty-five patients who underwent re-do robotic operation using trans-axillary approach for locoregional recurrent thyroid cancer from October 2007 to April 2021 at Yonsei University Hospital were analyzed. Completion total thyroidectomy (CTT) was performed in 26 cases, CTT and modified radical neck node dissection (mRND) in 16, and mRND in 23. Most of the re-do robotic operations were performed at site of previous incision. All patients were diagnosed with papillary thyroid carcinoma (PTC). CTT with central compartment neck dissection (CCND) took 117.6 ± 26.3 min, CTT with mRND 255.6 ± 38.6 min, and mRND, 211.7 ± 52.9 min. Transient hypocalcemia occurred in 17 (26.2%) patients and permanent hypocalcemia occurred in 3 (4.6%). There was one case of recurrent laryngeal nerve(RLN) injury. One patient was diagnosed with structural recurrence after re-do robotic operation. Median follow-up duration was 50.7 ± 37.1 months. Re-do robotic operation can be an alternative for patients who are diagnosed with locoregional recurrent thyroid cancer after thyroidectomy, with no increase in morbidity, similar oncologic outcomes, and superior cosmetic satisfaction.

[Postoperative hypocalcemia - the most common complication of endocrine head and neck surgery: acute management]

BACKGROUND

In Germany, 8000 patients are affected by postoperative hypoparathyroidism per year following surgery of the thyroid gland, parathyroidal glands and the larynx. Patients do not only suffer from paresthesia in the acute phase of this complication, but are also adversely affected by the fear of loss of control following episodes of tetany even years after the first episode.

OBJECTIVES

Discussion of a diagnostic pathway and presentation of a management pathway for postoperative hypocalcemia.

METHODS

Narrative review, analysis and discussion of current literature and expert recommendations.

RESULTS

Early determination of calcium and parathyroid hormone allows timely diagnosis and treatment of postoperative hypoparathyroidism. Active vitamin D is pivotal for the resorption of calcium. Only the combined treatment with active vitamin D and calcium can mitigate or prevent the postoperative drop of calcium levels.

CONCLUSIONS

A standard operating procedure (SOP) for postoperative hypoparathyroidism should be implemented in every surgical department. An SOP for diagnosis and treatment of postoperative hypoparathyroidism is proposed for institutional individualization and implementation.

The Optimal Parathyroid Hormone Cut-Off Threshold for Early and Safe Management of Hypocalcemia After Total Thyroidectomy

OBJECTIVE

To define optimal intact parathyroid hormone (iPTH) cut-off threshold predictive of hypocalcemia after total thyroidectomy for safe and effective postoperative management.

METHODS

This prospective single center study was done in 2 phases. In phase I, predictors of symptomatic hypocalcemia were analyzed and the receiver operating characteristic curve was used to define the optimal iPTH cut-off threshold predictive of hypocalcemia. Phase II studied giving prompt prophylactic supplemental calcium and vitamin D to all patients who had iPTH levels below the calculated threshold, while phase I patients were given prompt selective supplementation if they had postoperative hypocalcemia or symptoms.

RESULTS

Univariate analysis of patients in phase I showed that postoperative iPTH was the only significant variable that can predict symptomatic hypocalcemia. Using receiver operating characteristic curve and Youden index, the confirmed optimal cut-off threshold predictive of hypocalcemia was iPTH 19.95 pg/mL, with area under the curve of 0.903, 100% sensitivity, negative predictive value, and highest Youden index, while iPTH 15 pg/mL and iPTH 10 pg/mL were less optimal. Symptomatic hypocalcemia occurred in 30% of the phase I cohort who received selective supplementation versus 3% of those in the phase II cohort who received prophylactic supplementation. Return to emergency department and need for intravenous calcium were also significantly better in phase II.

CONCLUSION

iPTH cut-off for post-thyroidectomy hypocalcemia was 19.95 pg/mL. Low-risk patients were discharged with no supplementation while all high-risk patients received prompt calcium and vitamin D supplementation, which led to effective hypocalcemia management and safe 24-hour discharge.