Dynamics of PTH levels in the development of post-operative hypoparathyroidism

BACKGROUND

Post-operative hypoparathyroidism is the most frequent complication after total thyroidectomy. The identification of preoperative predictors could be helpful to identify patients at risk. This study aimed to evaluate the potential influence of preoperative PTH levels and their perioperative dynamics as a predictor of transient, protracted, and permanent post-operative hypoparathyroidism.

METHODS

A prospective, observational study that includes 100 patients who underwent total thyroidectomy between September 2018 and September 2020.

RESULTS

Transient hypoparathyroidism was present in 42% (42/100) of patients, 11% (11/100) developed protracted hypoparathyroidism, and 5% (5/100) permanent hypoparathyroidism. Patients who presented protracted hypoparathyroidism had higher preoperative PTH levels. The protracted and permanent hypoparathyroidism rate was higher in groups with greater preoperative PTH [0% group 1 (<40 pg/mL) vs. 5.7% group 2 (40-70 pg/mL) vs. 21.6% group 3 (>70 pg/mL); p = 0.03] and (0 vs. 8.3 vs. 20%; p = 0.442), respectively. The rate of protracted and permanent hypoparathyroidism was higher in patients with PTH at 24 h lower than 6.6 pg/mL and whose percentage of PTH decline was higher than 90%. The rate of transient hypoparathyroidism was higher in patients who showed a PTH decline rate of more than 60%. The percentage of PTH increase one week after surgery in patients with permanent hypoparathyroidism was significantly lower.

CONCLUSION

The prevalence of protracted hypoparathyroidism was higher in groups with higher preoperative PTH levels. PTH levels 24 h after surgery lower than 6.6 pg/mL and a decline of more than 90% predict protracted and permanent hypoparathyroidism. The percentage of PTH increase a week after surgery could predict permanent hypoparathyroidism.

The Effects of Radioiodine Therapy on the Recovery of Parathyroid Function in Patients with Protracted Hypoparathyroidism after Total Thyroidectomy for Papillary Thyroid Carcinoma

BACKGROUND

To determine the effect of 131I treatment on postoperative parathyroid function and the timing of recovery of parathyroid function (RPF) in patients with protracted hypoPT.

METHODS

260 patients with papillary thyroid cancer (PTC) were retrospectively analyzed, including 166 patients treated with radioactive iodine-131 (131I) classified into the 131I group and 94 patients without 131I treatment classified into the control group. Data on clinicopathological characteristics, demographics, dose and interval time of 131I treatment, number of parathyroid glands remaining in situ (PGRIS), occurrence of hypoPT, duration of RPF, preoperative and postoperative levels of Ca and PTH were collected.

RESULTS

The patients in the 131I group showed a higher persistent hypoPT rate than those in the control group (p = 0). The PGRIS and total number of PG were significantly higher in patients who recovered from protracted HypoPT (p = 0.02; p = 0.03). PGRIS and 131I treatment [1 ∼ 2 VS 0, p = 0.03, OR 3.19; 3 ∼ 4 VS 0, p = 0.02, OR3.62; p = 0.02, OR 1.98, respectively] were independent factors influencing postoperative persistent hypoPT. The timing of RPF differed significantly for patients in the control group compared to those in the 131I group [p = 0.00].

CONCLUSIONS

We found that 131I treatment significantly prolonged the RPF of patients with protracted hypoPT and caused late RPF (even beyond 12 months). The diagnosis of "permanent" hypoPT should be cautiously made at least 12 months after surgery, especially in patients who receive 131I treatment.

Indocyanine green angiography-guided thyroidectomy versus conventional thyroidectomy for preserving parathyroid function: study protocol for a randomized single-blind controlled trial

Introduction

Angiography with indocyanine green (ICG) fluorescence performed before thyroidectomy would allow identification of the vascularization of parathyroid glands, maximizing efforts for preserving functioning glands intraoperatively. The rationale of the study was based on the hypothesis that showing the vascular pattern of the parathyroid glands by means of ICG angiography before performing the thyroidectomy could prevent permanent hypoparathyroidism.

Methods and analysis

We propose a randomized single-blind controlled and multicenter clinical trial to assess the efficacy and safety of ICG angiography-guided thyroidectomy to identify the vascular pattern of the parathyroid glands versus conventional thyroidectomy in patients scheduled for elective total thyroidectomy. Patients will be randomized 1:1 to ICG angiography-guided thyroidectomy (experimental group) or conventional thyroidectomy (control group). Patients in the experimental group will undergo ICG angiography before thyroidectomy to identify the feeding vessels of the parathyroid glands and then, post-thyroidectomy ICG angiography to predict immediate parathyroid gland function by scoring the degree of fluorescence of the glands. Patients in the control group will undergo post-thyroidectomy ICG angiography only. The primary outcome measure will be the rate of patients with permanent hypoparathyroidism. Secondary outcome measures will be rate of postoperative hypoparathyroidism, the percentage of well vascularized parathyroid glands remaining in situ, the levels of iPTH and serum calcium after surgery and the influence of the type of vascular pattern of the parathyroid glands over these outcomes, as well as the safety profile of ICG angiography.

Discussion

The results will contribute to adopt a new surgical strategy based on intraoperative ICG angiography before performing total thyroidectomy, according to which the rate of permanent hypoparathyroidism could be substantially reduced.

Clinical trial registration

ClinicalTrials.gov. identifier NCT05573828.

[Predictive value of PTH level on day 1 after surgery for papillary thyroid carcinoma in patients with permanent hypoparathyroidism]

Objective:To investigate the relationship between parathyroid hormone（PTH） level and permanent hypoparathyroidism（PHPP） on the first day after radical papillary thyroidectomy, and its predictive value. Methods:A total of 80 patients with papillary thyroid cancer who underwent total thyroid resection and central lymph node dissection were collected and analyzed from January 2021 to January 2022. According to whether PHPP occurred after surgery, the patients were divided into hypoparathyroidism group and normal parathyroid function group, and univariate and binary logistics regression were used to analyze the correlation between PTH and serum calcium levels and PHPP on the first day after surgery in two groups. The dynamic changes of PTH at different time points after operation were analyzed. The area under the receiver operating characteristic was used to evaluate the predictive power of PTH on the development of PHPP after surgery. Results:Among the 80 patients with papillary thyroid cancer, 10 cases developed PHPP, with an incidence rate of 12.5%. Binary logistics regression analysis showed that PTH on the first postoperative day（OR=14.534, 95%CI: 2.377-88.858, P=0.004） was an independent predictive risk factor for postoperative PHPP. Taking PTH=8.75 ng/L on the first postoperative day as the cut-off value, the AUC of the area under the curve was 0.874（95%CI: 0.790-0.958, P<0.001）, the sensitivity was 71.4%, the specificity was 100%, and the Yoden index was 0.714. Conclusion:PTH level on the first day after total thyroid papillary carcinoma surgery is closely related to PHPP, and is an independent predictor of PHPP.

Intact parathyroid hormone value on the first postoperative day following total thyroidectomy as a predictor of permanent hypoparathyroidism: a retrospective analysis on 426 consecutive patients

INTRODUCTION

Hypoparathyroidism represents a common complication following total thyroidectomy. To date, there is still no reliable and immediate postoperative parameter to establish which patients with postsurgical hypoparathyroidism will develop permanent hypoparathyroidism. The main purpose of the present study was to assess whether the intact parathyroid hormone (iPTH) value on the first postoperative day is a good predictor of permanent hypoparathyroidism.

MATERIAL AND METHODS

Patients undergoing thyroidectomy in our unit between March 2018 and January 2020 were analysed. According to the iPTH value on the first postoperative day and on the basis of the detection threshold of the iPTH test used, patients were divided into two groups: Group A (iPTH ≥ 4.6 pg/mL) and Group B (iPTH < 4.6 pg/mL, undetectable).

RESULTS

In total 426 patients were included: 364 in Group A and 62 in Group B. Permanent hypoparathyroidism occurred in 3 (0.82%) patients from Group A and in 26 (41.94%) from Group B (p < 0.001). When iPTH levels were < 4.6 pg/mL on the first postoperative day the sensitivity for the prediction of permanent hypoparathyroidism was 89.66%, the specificity was 90.93%, the positive predictive value (PPV) was 41.94%, the negative predicitive value (NPV) was 99.18% and the accuracy was 90.85%.

CONCLUSIONS

An iPTH value < 4.6 pg/mL on the first postoperative day following total thyroidectomy has proven to be a good parameter for early identification of patients at high risk for permanent hypoparathyroidism. Moreover, we want to underline that in our experience no patient with an iPTH level > 6.5 pg/mL developed this complication.

Measurement of serum intact parathyroid hormone concentration 1 day after total thyroidectomy to assess risk of permanent hypoparathyroidism

OBJECTIVE

This study was performed to assess the clinical value of measuring the intact parathyroid hormone (iPTH) concentration 1 day after total thyroidectomy to estimate the occurrence of permanent hypoparathyroidism (pHPP).

METHODS

Data of 546 patients who underwent total thyroidectomy from February 2008 to December 2018 were retrospectively analyzed. Calcium and iPTH concentrations were collected preoperatively and at 1 day and 6 months postoperatively. Logistic regression was used to analyze the correlation between clinical indexes and postoperative pHPP.

RESULTS

Of the 546 patients, 22 (4.03%) developed pHPP. Multivariate analysis showed that the iPTH and serum calcium concentrations measured 1 day after surgery were independent predictors of the risk of pHPP. An iPTH concentration of 5.51 pg/mL measured 1 day postoperatively was used as the cut-off value, and the area under the curve was 0.956. The risk of pHPP was identified with a sensitivity of 100%, specificity of 85.1%, positive predictive value of 22%, and negative predictive value of 100%.

CONCLUSIONS

The iPTH concentration measured 1 day after total thyroidectomy is closely related to the occurrence of pHPP postoperatively and is an independent predictive risk factor. The postoperative iPTH concentration can be helpful in identifying patients at risk for developing pHPP.

Post-Operative Permanent Hypoparathyroidism and Preoperative Vitamin D Prophylaxis

Permanent hypoparathyroidism, a feared thyroidectomy complication, leads to significant patient morbidity, medical treatment, and monitoring. This study explores whether preoperative high-dose vitamin D loading decreases the incidence of permanent hypoparathyroidism. In a subgroup analysis, the study examines the predictive utility of day 1 parathyroid hormone (PTH) in permanent hypoparathyroidism. Patients (n = 150) were previously recruited in the VItamin D In Thyroidectomy (VIDIT) trial, a multicentre, randomised, double blind, placebo-controlled trial evaluating the role of 300,000 IU cholecalciferol administered orally a week before total thyroidectomy. Patients were contacted postoperatively beyond six months through a telephonic questionnaire. The primary outcome was permanent hypoparathyroidism, strictly defined as the need for activated vitamin D six months postoperatively. Out of 150 patients, 130 (86.7%) were contactable. Permanent hypoparathyroidism occurred in 11/130 (8.5%) patients, with a lower incidence of 5.3% (3/57) in the cholecalciferol group compared to 11% (8/73) in the placebo group; however, this was non-significant (p = 0.34). In a subgroup analysis, no relationship between day 1 PTH level and the incidence of permanent hypoparathyroidism was found (p ≥ 0.99). There was a lower rate of permanent hypoparathyroidism in the cholecalciferol group, which was not significant. The predictive utility of day 1 postoperative PTH levels may be limited to transient hypoparathyroidism.

Duration of Parathyroid Function Recovery in Patients With Protracted Hypoparathyroidism After Total Thyroidectomy for Papillary Thyroid Carcinoma

PURPOSE

The aim of the present study is to investigate the time to recovery of parathyroid function in patients with protracted hypoparathyroidism at 1 month after total thyroidectomy of papillary thyroid carcinoma.

MATERIALS AND METHODS

Adult patients who underwent total thyroidectomy for papillary thyroid cancer were included. Cases of long-term hypoparathyroidism were studied for recovery of parathyroid function during the follow-up. The duration of recovery and associated variables were recorded.

RESULTS

Out of the 964 patients, 128 (13.28%) developed protracted hypoparathyroidism and of these, 23 (2.39%) developed permanent hypoparathyroidism and 105 (10.89%) recovered: 86 (8.92%) before 6 months, 11 (1.14%) within 6 and 12 months and 8 (0.83%) after 1 year follow-up. Variables significantly associated with the time to parathyroid function recovery were number of autotransplanted parathyroid glands (HR, 1.399; 95% CI, 1.060 - 1.846; P = 0.018), serum calcium concentration >2.07 mmol/L (Hazard ratio [HR], 1.628; 95% confidence interval [CI], 1.009 - 2.628; P = 0.046) and PTH level > 1.2 pmol/L (HR, 1.702; 95% CI, 1.083 - 2.628; P = 0.021) at 1 month postoperatively.

CONCLUSION

Permanent hypoparathyroidism should not be diagnosed easily by time, since up to one-fifth of the patients will experience recovery after a period of 6 months and a few patients even beyond one year. The number of autotransplanted parathyroid glands is positively associated with the time to parathyroid function recovery.

Prevalence of basal ganglia and carotid artery calcifications in patients with permanent hypoparathyroidism after total thyroidectomy

OBJECTIVE

Permanent hypoparathyroidism is an uncommon disease resulting most frequently from neck surgery. It has been associated with visceral calcifications but few studies have specifically this in patients with post-surgical hypoparathyroidism. The aim of the present study was to assess the prevalence of basal ganglia and carotid artery calcifications in patients with long-term post-thyroidectomy hypoparathyroidism compared with a control population.

DESIGN

Case-control study.

METHODS

A cross-sectional review comparing 29 consecutive patients with permanent postoperative hypoparathyroidism followed-up in a tertiary reference unit for Endocrine Surgery with a contemporary control group of 501 patients who had an emergency brain CT scan. Clinical variables and prevalence of basal ganglia and carotid artery calcifications were recorded.

RESULTS

From a cohort of 46 patients diagnosed with permanent hypoparathyroidism, 29 were included in the study. The mean duration of disease was 9.2 ± 7 years. Age, diabetes, hypertension, smoking and dyslipidemia were similarly distributed in case and control groups. The prevalence of carotid artery and basal ganglia calcifications was 4 and 20 times more frequent in patients with permanent hypoparathyroidism, respectively. After propensity score matching of the 28 the female patients, 68 controls were matched for age and presence of cardiovascular factors. Cases showed a four-fold prevalence of basal ganglia calcifications, whereas that of carotid calcifications was similar between cases and controls.

CONCLUSION

A high prevalence of basal ganglia calcifications was observed in patients with post-surgical permanent hypoparathyroidism. It remains unclear whether carotid artery calcification may also be increased.

A new classification of parathyroid glands to evaluate in situ preservation or autotransplantation during thyroid surgery

The indication for autotransplantation of parathyroid glands is still controversial. A new classification of parathyroid glands based on the positional relationship among parathyroid glands, thyroid gland and thymus was created to decide in situ preservation or autotransplantation during thyroid surgery.A retrospective study included patients with papillary thyroid cancer who underwent total thyroidectomy with bilateral central lymph node dissection between November 2014 and November 2016. According to the application of the new classification (December 2015-November 2016) or traditional method (preservation of all functional parathyroid glands in situ, November 2014-November 2015), the patients were divided into new classification and traditional groups.The traditional method was utilized in 288 patients who underwent surgery during the first half of the study, while the new classification was applied to 249 patients during the latter half of the study. The incidence of transient hypoparathyroidism was 43.0% (107/249) in new classification group and 35.8% (103/288) in the traditional group, respectively (P = .093). The corresponding incidence of permanent hypoparathyroidism was 0.4% (1/249) and 4.5% (13/288) (P = .002).The new classification of parathyroid glands potentially reflects the difficulty of preservation and helps to make a reasonable decision on preservation or autotransplantation of a parathyroid gland, which may minimize the incidence of permanent hypoparathyroidism.

Fresh tissue parathyroid allotransplantation with short-term immunosuppression: 1-year follow-up

BACKGROUND

Permanent hypoparathyroidism is a serious problem and requires medications indefinitely. Parathyroid allotransplantation (PA) with short-term immunosuppression is definitive choice but long-term results are not clear.

METHOD

We performed PA from two donors to two recipients. Both recipients were 39-year-old females. Donors were a 32-year-old female and a 36-year-old male, who both have chronic kidney disease. Routine tests, viral markers, and cross-matches were analyzed individually. The parathyroid glands were resected from the living donors, fragmented quickly in the operation room and injected into the left deltoid muscles of the two recipients.

RESULTS

Methylprednisolone was administered on post-PA day one and two. Recipients were discharged from the hospital without complications. Calcium and PTH levels were observed throughout 1 year. We did not observe any complications during the follow-up period. Medications ceased in post-transplantation week 1 for Case 1 and after 1 month for Case 2.

CONCLUSION

Fresh tissue PA with short-term immunosuppression appears to be a promising technique that is easy to perform, is cost-effective, has low risk of side effects and minimal complications with compatibility for HLA conditions. A longer follow-up period and more case studies are needed to determine the risks and benefits of this procedure for future cases.

Analysis of the factors that have an effect on hypocalcemia following thyroidectomy

OBJECTIVE

The incidence of and risk factors for hypocalcemia following thyroidectomy were evaluated in this study.

MATERIAL AND METHODS

One hundred and ninety thyroidectomy patients were evaluated retrospectively for factors that might contribute to postoperative hypocalcemia; age, hyperthyroidism, malignancy, the extent of surgery (total/near total/subtotal thyroidectomy), cervical lymph node dissection, and incidental parathyroidectomy.

RESULTS

The rate of transient hypocalcemia/hypoparathyroidism was 19.47%, with a permanent hypoparathyroidism rate of 4.74%. Factors affecting the development of transient hypocalcemia were found as being operated for hyperthyroidism, and use of total thyroidectomy as the surgical method. Total thyroidectomy increased the risk of postoperative hypocalcemia by 3.16 fold. Patients undergoing operations for hyperthyroidism had a 2.3 fold increase, and those undergoing total thyroidectomy had a 3.16 fold risk of postoperative hypocalcemia.

CONCLUSION

Hyperthyroidism surgery and total thyroidectomy lead to a higher risk of developing early postoperative or transient hypocalcemia. According to our results, no significant relationship could be established between any of the study parameters and persistent hypocalcemia.