Early Discharge and Selective Calcium Supplementation after Thyroidectomy Based on Post-Operative Day 1 Parathormone and Calcium Level: A Prospective Study

Accuracy of Serum Parathyroid Hormone Measured on the Early Morning of the First Postoperative Day in Predicting Clinically Significant Post-Total Thyroidectomy Hypocalcemia

INTRODUCTION

Clinical hypocalcemia (CH) following total thyroidectomy (TT) is a potentially life-threatening condition if left untreated. This study aimed at evaluating the accuracy of parathyroid hormone (PTH) measured in the early morning of the first postoperative day (POD-1) in predicting CH, and determining the cutoff values of PTH that can predict the development of CH.

METHODS

We performed a retrospective review of patients undergoing TT between February 2018 and July 2022. Serum PTH, calcium, and albumin levels were measured on morning (6-8 AM) of postoperative day one (POD-1), and serum calcium level was measured from POD-2 onwards. We performed ROC curve analysis to determine the accuracy of PTH in predicting postoperative CH, and cutoff values of PTH to predict CH.

RESULTS

Ninety-one patients, 52 (57.1%) with benign and 39 (42.9%) with malignant goiter were included. The incidence of biochemical, and clinical hypocalcemia was 24.2% and 30.8%, respectively. In our study serum, PTH measured in the early morning of first postoperative day following TT was found to have good accuracy (AUC = .88) in predicting CH. A PTH value of ≥27.15 pg/mL was found to have a 96.4% sensitivity in ruling out CH, while a serum PTH value <10.65 pg/mL had a specificity of 95.2% in predicting CH.

DISCUSSION

Patients with a serum PTH value of ≥27.15 pg/mL can be discharged without any supplements, those with PTH <10.65 pg/mL should be started on calcium and calcitriol supplements, while patients having PTH values between 10.65 and 27.15 pg/mL should be monitored for the development of signs and/or symptoms of hypocalcemia.

Establishing a predictive model of hypoparathyroidism after total thyroidectomy and central lymph node dissection for postoperative calcium supplementation selectively

Background

The core goal of this article is to find some meaningful risk factors that can affect the postoperative hypoparathyroidism of thyroid cancer, create an effective prediction model on this basis, and use it to selectively implement routine prophylactic calcium supplementation for patients after thyroid carcinoma surgery.

Methods

The clinicopathological characteristics of patients with papillary thyroid carcinoma (PTC) who underwent conventional bilateral total thyroidectomy (TT) + bilateral central lymph node dissection from January 2020 to August 2021 in the Affiliated Hospital of Nantong University were retrospectively analyzed. Firstly, this study analyzed the relationship between postoperative hypocalcemia and hypoparathyroidism. Then, we included many potential risk factors such as gender, age, body mass index (BMI), lateral lymph node dissection (LLND) and so on and also performed univariate and multivariate analysis of the independent risk factors for postoperative hypoparathyroidism in patients, and established a predictive scoring model.

Results

Among the 401 patients with PTC, 50.1% developed postoperative hypoparathyroidism. There was significant difference in serum calcium concentration between normal parathyroid group and hypoparathyroidism group after thyroid carcinoma surgery. BMI <24 kg/m², lateral lymph node dissection, multifocality, and extrathyroidal extension (ETE) were all identified as independent risk factors for postoperative hypoparathyroidism. Based on these independent risk factors, a nine-point risk scoring model was created to firstly assess the postoperative parathyroid function status of patients and then to determine whether routine prophylactic calcium supplementation is needed. Importantly, the area under the curve (AUC) of the risk scoring model is equal to 0.979.

Conclusions

At present, prophylactic calcium supplementation after thyroid carcinoma surgery is a controversial postoperative treatment. It should be selectively implemented for high-risk patients with hypoparathyroidism after surgery. Routine prophylactic calcium supplementation is recommended for PTC patients with a score greater than or equal to 5, although there are no clinical symptoms of postoperative hypocalcemia caused by hypoparathyroidism. However, prophylactic calcium supplementation is not recommended for patients with PTC with a score of less than 5; if the patient develops hypocalcemia at the later stage, therapeutic calcium supplementation can then be implemented.

The utility of indocyanine green (ICG) for the identification and assessment of viability of the parathyroid glands during thyroidectomy

We conducted this study to evaluate the ability of indocyanine green (ICG) and near infra-red fluorescence (NIRF) camera to aid in the identification and assessment of viability of parathyroid glands during thyroid surgery. A prospective observational study was conducted between May and October 2020 among 50 consecutive patients who underwent total thyroidectomy at a single institution. Parathyroid glands were identified under white light during thyroidectomy following which reconstituted ICG was injected through a peripheral vein and the location of parathyroid glands was confirmed. The perfusion to the parathyroid gland was assessed by documenting the fluorescence intensity score (FIS) and the parathyroid angiogram score (PAS). There was no difference in the number of parathyroid glands seen on visual inspection 147 (73.5%) when compared to under NIRF camera, 146 (73%). Though the rate of postoperative hypoparathyroidism was lower in the cohort with FIS 3 (14.2%) compared to score 2 and 1 (28.5% and 100%, respectively), this was not significant (p = 0.35). A significant correlation was noted between a delayed flow on PAS and the development of post-thyroidectomy hypoparathyroidism (p = 0.01). PAS had a sensitivity of 100%, specificity of 88.6%, NPV of 100% and PPV of 55.6% to predict the development of post-thyroidectomy hypoparathyroidism. In this study, there was no additional benefit of ICG and NIRF camera in the identification of parathyroid glands. However, ICG angiogram seems to be a good adjunct for the intraoperative assessment of the viability of the parathyroid glands and accurately predicts the development of postoperative hypoparathyroidism.

PTH after Thyroidectomy as a Predictor of Post-Operative Hypocalcemia

Post-thyroidectomy hypocalcemia is a frequent complication with significant morbidity, and has been shown to increase hospital stay and readmission rates. The evaluation of serum parathyroid hormone (PTH) levels after thyroidectomy represents a reliable method to predict post-thyroidectomy hypocalcemia, but it remains infrequently used. This retrospective study investigates serum PTH values 3 h after thyroidectomy as a predictor of hypocalcemia. In this study, we enrolled 141 patients aged between 27 and 71 years eligible for total thyroidectomy who presented with multinodular goiter, suspicious nodule on cytological examination, Graves’ disease, or toxic multinodular goiter. Three hours after total thyroidectomy, 53 patients (37.6%) showed a reduction in serum PTH. Of these patients 75.5% developed hypocalcemia by 24 h after surgery and 100% were hypocalcemic after 48 h (p < 0.001). There was no significant difference attributable to the different thyroid diseases, nor to the age of the patients. PTH at 3 h after total thyroidectomy accurately predicts post-operative hypocalcemia. The early detection of patients at risk of developing post-operative hypocalcemia allows for prompt supplementation of calcium and Vitamin D in order to prevent symptoms and allows for a safe and timely discharge.

Efficacy of Fluorescein Green Dye in Assessing Intra-Operative Parathyroid Gland Vascularity and Predicting Post-Thyroidectomy Hypocalcaemia- A Novel Prospective Cohort Study

BACKGROUND

Postoperative hypocalcaemia (POH) after total thyroidectomy (TT) is a common complication. Parathyroid hormone (PTH), an accurate predictor of POH cannot assess intra-operative viability of parathyroid glands (PGs). Different dyes including indocyanine green or carbon nanoparticles have been used, but they are expensive and not widely available. Fluorescein green dye (FD) has been used as a low-cost alternative to study viability of various organs, but seldom tried in visualizing PGs. This novel study aims to assess utility of FD in determining parathyroid viability and predicting POH.

MATERIAL AND METHOD

Total 72 out of 88 patients undergoing TT between January and December 2019 were included. Two ml of 25% FD was given intravenously before wound closure and attempts were made to visualize PGs under blue light. A numerical score was given according to the number of PGs visualized. Intact-PTH and corrected calcium were measured on postoperative day 1 and patients observed for POH.

RESULTS

No PGs were visualized in 6 patients, 1 in 13, 2 in 30, 3 in 16 & 4 in 7 patients. Mean PTH was 6, 16.9, 31.6, 33.2 and 48.5 respectively. Corrected-calcium was 7.08, 7.7, 7.9, 8.5 and 8.5 respectively. All patients with score 0 received supplementary IV calcium, while 53.8% (score-1), 30% (score-2), 0% (scores-3, 4) received the same. Sensitivity, specificity and ROC of PG score of ≥2 on FD in predicting POH were 100%, 44% and 0.83 respectively.

CONCLUSION

FD visualization of parathyroids post TT is feasible and can be used as low cost efficacious method to predict POH.