Normal parathyroid hormone levels do not exclude permanent hypoparathyroidism after thyroidectomy

Parathyroid-on-a-chip simulating parathyroid hormone secretion in response to calcium concentration

The parathyroid gland is an endocrine organ that plays a crucial role in regulating calcium levels in blood serum through the secretion of parathyroid hormone (PTH). Hypoparathyroidism is a chronic disease that can occur due to parathyroid defects, but due to the difficulty of creating animal models of this disease or obtaining human normal parathyroid cells, the evaluation of parathyroid functionality for drug development is limited. Although parathyroid-like cells that secrete PTH have recently been reported, their functionality may be overestimated using traditional culture methods that lack in vivo similarities, particularly vascularization. To overcome these limitations, we obtained parathyroid organoids from tonsil-derived mesenchymal stem cells (TMSCs) and fabricated a parathyroid-on-a-chip, capable of simulating PTH secretion based on calcium concentration. This chip exhibited differences in PTH secretion according to calcium concentration and secreted PTH within the range of normal serum levels. In addition, branches of organoids, which are difficult to observe in animal models, were observed in this chip. This could serve as a guideline for successful engraftment in implantation therapies in the future.

An individual approach to intraoperative parathyroid hormone measurement during total thyroidectomy

PURPOSE

Hypocalcemia is a common complication of thyroidectomy. Measurement of the intraoperative serum parathyroid hormone (PTH) levels became an established technique but it requires further improvements. We aimed to assess intraoperative PTH level testing results against the hypothesis that the PTH assay may be performed almost immediately after thyroid gland removal.

METHODS

A retrospective cohort study. During total thyroidectomy surgery, the patients had PTH levels measured at the cutting time and again immediately after the thyroid gland is removed. Post-operatively, serial total blood calcium levels were obtained twice daily and recorded.

RESULTS

Among 63 enrolled patients, 39 had multinodular goiter, 15 thyroid carcinoma, and nine had Graves' disease. The mean age was 59.8 ± 15.3 years, 43 females. The mean PTH level before surgery was 45.8 ± 22.0 pg/mL. Post-operatively, 11/63 patients developed hypocalcemia with serum calcium levels <8 mg/dL. Four patients with ≥50 % decrease in PTH concentration were normocalcemic a day after surgery and were discharged early. Four patients with ≥70 % PTH decrease were treated accordingly during prolonged hospitalization and did not suffer from permanent hypocalcemia. The cut-off value of 70 % decrease after the gland removal was able to predict postoperative hypocalcemia with a sensitivity of 100 %, specificity 82.9 %, PPV 60.0 % and NPV 100 %.

CONCLUSION

Measurements of intraoperative PTH may not be performed at fixed time intervals but after 1-2 min after removal of the thyroid gland. Defining those not at risk would allow the majority of patients to be waived from post-operative blood calcium testing and safely discharged early after surgery.

Incidence of post-surgical hypoparathyroidism (POSH) after total thyroidectomy

Post-surgical hypoparathyroidism (POSH) is a recognised complication of total thyroidectomy, leading to hypocalcaemia and its associated adverse effects. This retrospective study aimed to determine the incidence of POSH and identify perioperative predictors for its development. Data from patients who underwent total or completion thyroidectomy between January 2017 and July 2022 were retrospectively analysed. The incidence of POSH was assessed, and patients were categorised into transient or prolonged POSH at six months postoperatively. Potential predictors for POSH were investigated including gender, histological diagnosis, and preoperative thyroid function. A total of 133 adult patients were included in the study. The incidence of patients recovering from transient POSH within six months was 15%, and 5% had prolonged POSH beyond six months of surgery. Parathyroid hormone (PTH) levels normalised in 83% of prolonged POSH patients within 14-33 months, reducing the incidence of persistent POSH to 0.75%. Despite normal PTH levels, overall, 3% had persistent marginally low calcium levels (mean 2.11 mmol/L) in keeping with relative parathyroid insufficiency. Histological diagnosis of malignancy was the only significant risk factor for both transient and prolonged POSH (RR 2.95, CI 1.54 to 5.67, p = 0.001) in this cohort. Cautious capsular dissection during thyroidectomy and protection of the parathyroid glands and vascular supply produce a low incidence of POSH. Although the vast majority of patients with POSH recover after six months, hypocalcaemia may persist due to relative parathyroid insufficiency, requiring long-term calcium supplementation. Further research is needed to determine the best strategies for preventing and treating this condition.

Incidence and risk factors of hypoparathyroidism and hypocalcemia after hemithyroidectomy

PURPOSE

The incidence and risk factors for hypoparathyroidism after total thyroidectomy is well-known. However, the characteristics of hypoparathyroidism and hypocalcemia after hemithyroidectomy have not been investigated well. In this study, we aimed to evaluate the incidence, characteristics, and risk factors of hypoparathyroidism and hypocalcemia after hemithyroidectomy.

METHOD

We retrospectively analyzed the medical data of 321 patients who underwent hemithyroidectomy, with or without central neck dissection, from January 2012 to April 2019. We analyzed the serum intact parathyroid hormone (iPTH), calcium, and ionized calcium (iCa) levels serially (preoperatively and postoperatively on the operation day; days 1 and 3; and months 1, 3, 6, and 12) and evaluated risk factors for postoperative hypoparathyroidism and hypocalcemia.

RESULTS

The mean iPTH and calcium levels decreased significantly after hemithyroidectomy on the operation day and postoperative days 1 and 3, and returned to the preoperative level at the postoperative 1-month follow-up. The mean iCa level decreased significantly on the operation day and postoperative day 1. Transient hypoparathyroidism and transient hypocalcemia occurred in 16 (5%) and 250 (78%) participants, and they recovered to normal levels postoperatively by 1 month. Eight (2.5%) patients had mild symptoms of hypocalcemia necessitating oral calcium supplementation. No permanent hypoparathyroidism or hypocalcemia was observed. Preoperatively low serum iPTH and calcium levels were associated with transient hypoparathyroidism and hypocalcemia after hemithyroidectomy.

CONCLUSION

Approximately 5% and 2.5% of participants showed transient hypoparathyroidism and mild symptomatic hypocalcemia after hemithyroidectomy. The risk factors for transient hypoparathyroidism and hypocalcemia include preoperative low serum iPTH and calcium levels.

Postoperative hypoparathyroidism after thyroid operation and exploration of permanent hypoparathyroidism evaluation

Background

To investigate the risk factors for hypoparathyroidism, discuss the prevention of postoperative hypoparathyroidism, and explore permanent postoperative hypoparathyroidism evaluation (PPHE).

Methods

A total of 2,903 patients with thyroid nodules were treated between October 2012 and August 2015. Serum calcium and intact parathyroid hormone (iPTH) levels were measured at 1 day, 1 month, and 6 months postoperatively. The incidence and management of hypoparathyroidism were analyzed. The PPHE was established based on the risk factors and clinical practice.

Results

A total of 637 (21.94%) patients developed hypoparathyroidism, and 92.15% of them had malignant nodules. The incidence rates of transient and permanent hypoparathyroidism were 11.47% and 10.47%, respectively. The iPTH level was lower in patients with malignant nodules who underwent total thyroidectomy (TT) and central-compartment neck dissection (CND). These factors were independently associated with the recovery rate of parathyroid function. The formula for PPHE is as follows: {iPTH} + {sCa} + {surgical procedure} + {reoperation} + {pathologic type}. A scoring system was developed, and we scored low, middle, and high risk of permanent postoperative hypoparathyroidism as 4-6, 7-9, and 10-13, respectively. The differences in the recovery rates of parathyroid function in several risk groups were statistically significant (p < 0.001).

Conclusion

Simultaneous TT and CND is a risk factor for hypoparathyroidism. The reoperation is not associated with hypoparathyroidism. Identification of parathyroid glands in situ and preservation of their vascular pedicles are key factors in managing hypoparathyroidism. PPHE can forecast the risk of permanent postoperative hypoparathyroidism well.

Bilateral and Ipsilateral Central Neck Dissection in Total Thyroidectomy: a Long Term Comparison of Complications

The role of prophylactic central compartment neck dissection (CCND) in total thyroidectomy (TT) is controversial in patients without clinically evident lymph nodes metastasis (cN0) because of association with transient and permanent hypoparathyroidism (HPT) as well as transient and permanent recurrent laryngeal nerve (RLN) injury. Instead of bilateral central neck dissection (bCCND), ipsilateral central compartment neck dissection (iCCND) has recently been proposed as a safer, alternative treatment for selected patients. The aim of this study is to characterize the morbidity that CCND (ipsilateral and bilateral) adds to TT. We enrolled 453 patients: Group A (316 patients) underwent TT alone, Group B (86 patients) underwent TT + iCCND, Group C (51 patients) underwent TT + bCCND. We compared the rates of RLN injury and HPT in three groups and data analysis showed that iCCND was associated with increased rate of transient HPT but not permanent HPT and bCCND was associated with increased rate of transient and permanent HPT, when compared with TT alone. Further studies are needed to evaluate the clear advantages of CCND (both ipsilateral and bilateral), but this should be considered in the context of an higher risk of surgical complications (especially transient and permanent hypoparathyroidism), in comparison with TT alone.

Actual prevalence of hypoparathyroidism after total thyroidectomy: a health insurance claims-database study

PURPOSE

Persistent hypoparathyroidism (hypoPT) is a major complication of total thyroidectomy. Nonetheless, previous reports may have underestimated the prevalence of hypoPT due to patient selection bias. We aimed to estimate the actual prevalence of persistent hypoPT after total thyroidectomy and to find predictive factors for postoperative hypoPT.

METHODS

This study retrospectively reviewed data from a health insurance claims-based database provided by the Japan Medical Data Center Co., Ltd. From 2009 to 2019, 2388 patients who underwent total thyroidectomy were identified using the medical procedure codes. Persistent hypoPT was defined as the prescription of active vitamin D supplements for >1 year postoperatively and the assignment of hypoPT codes. The prevalence of persistent hypoPT was estimated at two different levels: minimum and maximum estimations with or without postoperative osteoporosis and/or renal failure codes. Correlates for persistent hypoPT were investigated among several demographic and clinical variables.

RESULTS

Of the 2388 patients, 1752 (73.4%) were women with a mean age of 45 years. The types of diseases were: benign thyroid disease (n = 235), malignant thyroid tumors (n = 1570), Graves ' disease (n = 558), and malignancy combined with Graves' disease (n = 25). The minimum and the maximum estimation of the prevalence of persistent hypoPT were 15.0 and 20.3%, respectively. Multivariate logistic regression analysis showed that the malignant tumor (odds ratio, 1.8) independently correlated with persistent hypoPT.

CONCLUSIONS

The prevalence of persistent hypoPT after total thyroidectomy estimated by the claims-based database was higher than previously recognized. Comprehensive attempts to preserve parathyroid function, especially in malignant diseases, are essential.

Parameters for Calcium Metabolism in Women with Polycystic Ovary Syndrome Who Undergo Stimulation with Letrozole: A Prospective Cohort Study

For women with polycystic ovarian syndrome (PCOS) and infertility, stimulation with the aromatase-inhibitor letrozole has been recommended as a first-line for ovulation induction. Calcium-associated signaling has also been a component for other ovulation induction and superovulation medications. This study’s aim was to evaluate parameters of calcium metabolism in PCOS women. In a prospective cohort study, 61 anovulatory, infertile PCOS patients who underwent letrozole stimulation were included. Outcome measures were: follicular maturation after letrozole stimulation; parathyroid hormone (PTH); 25-hydroxyvitamin D3 (25OHD3); serum levels of calcium, phosphorus, magnesium, albumin, and total protein. Successful recruitment of a dominant follicle was achieved in 35 patients (57.4%). Women with and without successful follicular development did not differ in serum levels of PTH (38.4 ± 19.7 vs. 39.6 ± 16.2 pg/mL), 25OHD3 (62.5 ± 32.1 vs. 65.4 ± 30.9 nmol/L), calcium (2.36 ± 0.08 vs. 2.37 ± 0.12 mmol/L), or protein (70.2 ± 13.3 vs. 74.0 ± 3.7 g/L), respectively (p > 0.05). However, women who were not responsive to letrozole for ovulation induction demonstrated higher anti-Müllerian hormone (AMH) levels (9.7 ± 4.7 vs. 5.0 ± 3.2 ng/mL, p = 0.005). In conclusion, the success of letrozole stimulation in women with PCOS is independent from calcium metabolism parameters. However, AMH levels seem predictive of medication resistance.

Can preoperative 25-hydroxyvitamin D levels predict transient hypocalcemia after total thyroidectomy?

Transient postoperative hypocalcemia is a common complication after total thyroidectomy. Evidence on contributing metabolic factors is contradictory. Our work aims to define the role of preoperative 25-hydroxyvitaminD levels in developing transient postoperative hypocalcemia. 183 consecutive patients who underwent total thyroidectomy at our institution (May 2017–December 2019) were included in the retrospective study. We reported gender, age, estimated glomerular filtration rate, creatinine, preoperative 25-hydroxyvitaminD, serum pre- and postoperative calcium, pre- and postoperative PTH levels and transient postoperative hypocalcemia occurrences. We compared variables both among patients with and without transient postoperative hypocalcemia and between patients with different 25-hydroxyvitaminD levels (< 10 ng/ml deficitary; 11–30 ng/ml insufficient; > 30 ng/ml, normal). A binomial logistic regression model evaluating the risk for transient postoperative hypocalcemia was elaborated. Patients with transient postoperative hypocalcemia had lower levels of postoperative PTH (p < 0.001) and more frequently normal or deficitary 25-hydroxyvitaminD levels (p = 0.05). When comparing patients according to their 25-hydroxyvitaminD levels, insufficiency was associated with a lower rate of transient postoperative hypocalcemia (p = 0.05); deficiency was associated with higher preoperative PTH (p = 0.021), postoperative PTH (p = 0.043) and estimated glomerular filtration rate (p = 0.031) and lower serum creatinine (p = 0.014). In the regression model higher preoperative PTH (OR = 1.011, p = 0.041) and 25-hydroxyvitaminD deficiency (OR = 0.343, p = 0.011) significantly predicted transient postoperative hypocalcemia. Data analysis revealed a correlation between transient postoperative hypocalcemia and 25-hydroxyvitaminD levels: our work points towards the possibility to stratify the risk of transient postoperative hypocalcemia according to patients’ preoperative 25-hydroxyvitaminD status.

Risk Factors for Low Levels of Parathyroid Hormone after Surgery for Thyroid Cancer: A Single Center Study

Background: Thyroidectomy is the definitive treatment for most patients with thyroid cancer. Hypoparathyroidism is the most frequent complication of thyroidectomy, and its pathogenesis is multifactorial. The aim of this study is to evaluate the patient- and surgical-related risk factors for hypoparathyroidism after surgery for thyroid cancer. Methods: In this retrospective study, patients referred to surgery for thyroid cancer from 2016 to 2019 were enrolled. Preoperative serum calcium and parathyroid hormone (PTH) and postoperative 24 h PTH and calcium levels were evaluated. Demographic data, type of surgery, incidence of hypoparathyroidism and hypocalcemia were recorded for all the patients. Patients were divided into two groups based on post-operative PTH levels (≤12 and >12 pg/mL). Results: A total of 189 patients were enrolled in this study. There were 146 women (87.3%) and 43 men (22.7%), with a mean age of 51.3 years. A total of 79 patients (41.7%) underwent a neck dissection. A total of 59 patients (31.1%) had a postoperative PTH level < 12 pg/mL. Female sex, neck dissection, the yield of lymph node dissection and incidental parathyroidectomy were significantly associated with postoperative hypoparathyroidism. Incidental parathyroidectomy was reported in 44 (23.2%) patients and was correlated with younger age (<40 years) and neck dissection. There was no difference in the rate of post-operative hypocalcemia between patients with incidental parathyroidectomy and those without. Conclusions: Young patients undergoing neck dissection and with incidental parathyroidectomy have the highest risk of postoperative hypoparathyroidism after surgery for thyroid cancer. However, a large proportion of patients without incidental parathyroidectomy may have temporary hypocalcemia, suggesting that impaired blood supply of parathyroid glands during their identification and dissection may play a relevant role.

Role of postoperative intact serum PTH as an early predictor of severe post-thyroidectomy hypocalcemia: a prospective study

BACKGROUND

Post thyroidectomy hypocalcemia is a major sequel of thyroidectomy and continues to trouble the endocrinologists and the endocrine surgeons as there is no ideal predictive marker of hypocalcemia which has the potential to develop into a life-threatening complication. The role of early serum intact parathormone (iPTH) to predict post thyroidectomy hypocalcemia is becoming useful but the literature is still unclear regarding the optimal time of testing and the optimal cut-off value of serum iPTH.

PATIENTS AND METHODS

This is a prospective cohort study of 111 patients who underwent total thyroidectomy in a tertiary care endocrine surgery referral unit. Serum iPTH was measured after 20 min and 4 h of surgery. Receiver-Operator characteristic Curve (ROC) was used to find out of the best cut-off value of S. iPTH 20 min and 4 h after surgery in predicting hypocalcemia.

RESULTS

Hypocalcemia was noted in 60 (54%) out of 111 subjects who underwent total thyroidectomy. The best cut-off values of Serum iPTH to predict hypocalcemia was found to be 4.28 pmol/l at 20 min post total thyroidectomy with a sensitivity and specificity of 81.7% and 51%, respectively. In addition, patients with malignancy or central lymph nodal dissection were significantly over-represented in the hypocalcemia group with serum iPTH above the threshold level of 4.28 pmol/l. Below the cut off level, parenteral calcium supplementation was required in 23% (17/74) subjects while the rate was only 5.4% (2/37) patients when serum iPTH was above the cut-off level.

CONCLUSIONS

The decline of serum iPTH below a specific level after surgery has predictive value together with other factors strictly related to patient, the thyroid disease itself and surgery. The risk of development of hypocalcemia and consequent need for calcium supplementation should be evaluated by clinical assessment along with serum PTH measurement.

Total versus near-total thyroidectomy in Graves' disease: a systematic review and meta-analysis of comparative studies

Background

Total thyroidectomy (TT), near-total thyroidectomy (NT), and subtotal thyroidectomy (ST) are three surgical procedures for Graves' disease (GD) patients, but most previous studies have only evaluated the complications of TT versus ST or TT/NT versus ST; there is not a meta-analysis of NT versus TT, so whether NT is superior to TT for GD patients still unclear.

Methods

We comprehensively searched PubMed, Embase, Web of Science, and the Cochrane Library, without restriction to region, publication type, or language, on 10 June, 2020. We conducted this systematic review and meta-analysis of all included studies assessing the two surgical procedures.

Results

In total, 528 cases were identified from two randomized controlled trials (RCTs) and three retrospective studies. The incidence of permanent hypoparathyroidism after NT was lower than with TT [odds ratio (OR), 0.22; 95% confidence interval (CI), 0.06-0.80; P=0.02], and there was no statistical difference in the recurrence of hyperthyroidism (OR, 0.33; 95% CI, 0.01-8.12; P=0.50) and other postoperative complications (P>0.05).

Conclusions

NT for GD was superior to TT regarding permanent hypoparathyroidism, but there was no significant difference in preventing recurrent hyperthyroidism, as well as the other postoperative complications.

Incidental parathyroidectomy in thyroidectomy and central neck dissection

BACKGROUND

Although higher thyroidectomy volume has been linked with lower complication rates, its association with incidental parathyroidectomy remains less studied. The volume relationship is even less clear for central neck dissection, where individual parathyroid glands are at greater risk.

METHODS

Patients undergoing thyroidectomy with or without central neck dissection were evaluated for incidental parathyroidectomy, hypoparathyroidism, and hypocalcemia. Univariate and multivariable analyses were performed using binary logistic regression.

RESULTS

Overall, 1,114 thyroidectomies and 396 concurrent central neck dissections were performed across 7 surgeons. Incidental parathyroidectomy occurred in 22.4% of surgeries (range, 16.9%-43.6%), affecting 7.1% of parathyroids at risk (range, 5.8%-14.5%). When stratified by surgeon, lower incidental parathyroidectomy rates were associated with higher thyroidectomy volumes (R² = 0.77, P = .008) and higher central neck dissection volumes (R² = 0.93, P < .001). On multivariable analysis, low-volume surgeon (odds ratio 2.94, 95% confidence interval 2.06-4.19, P < .001), extrathyroidal extension (odds ratio 3.13, 95% confidence interval 1.24-7.87, P = .016), prophylactic central neck dissection (odds ratio 2.68, 95% confidence interval 1.65-4.35, P <.001), and therapeutic central neck dissection (odds ratio 4.44, 95% confidence interval 1.98-9.96, P < .001) were the most significant factors associated with incidental parathyroidectomy. In addition, incidental parathyroidectomy was associated with a higher likelihood of temporary hypoparathyroidism (odds ratio 2.79, 95% confidence interval 1.45-5.38, P = .002) and permanent hypoparathyroidism (odds ratio 4.62, 95% confidence interval 1.41-5.96, P = .025), but not permanent hypocalcemia (odds ratio 1.27, 95% confidence interval 0.48-3.35, P = .63). Higher lymph node yield in central neck dissection was not associated with higher incidental parathyroidectomy rates (odds ratio 1.13, 95% confidence interval 0.85-8.81, P = .82).

CONCLUSION

Higher surgical volume conferred a lower rate of incidental parathyroidectomy. Nonetheless, greater lymph node yield in central neck dissections did not result in greater parathyroid-related morbidity. Such findings support the value of leveraging surgical volume to both optimize oncologic resection and minimize complication rates.

Parathormone decline levels are better markers of symptomatic hypocalcemia following total thyroidectomy than parathormone alone

Background: We aimed to assess the predictive value of the absolute and relative intact parathormone (iPTH) decline levels as reliable markers of postoperative hypocalcemia. Materials & methods: iPTH levels were measured 4 h after surgery and the following morning after surgery (postoperative day 1). iPTH, absolute iPTH decline (ΔPTH) and relative iPTH decline (ΔPTH%) were calculated and correlated with symptomatic hypocalcemia. Results: Of the 95 patients, 20% of patients (n = 19) developed symptomatic hypocalcemia. The ΔPTH (U = 206; p < 0.001) and ΔPTH% (U = 127; p < 0.001) were significantly higher in patients with symptomatic hypocalcemia. A ΔPTH% of 20% (sensitivity of 84%; specificity of 91%); and an absolute iPTH decline of 3.75 pg/ml (sensitivity of 74%; specificity of 87%) were highly predictive of symptomatic hypocalcemia. Conclusion: Postoperative ΔPTH and ΔPTH% have the potential to be predictors of symptomatic hypocalcemia following thyroidectomy and could facilitate a safe early discharge.

Incidence, Risk Factors, and Clinical Implications of Delayed Hypoparathyroidism on Postoperative Day two Following Total Thyroidectomy for Papillary Thyroid Carcinoma

OBJECTIVE

This study aimed to investigate the incidence rates, risk factors, and clinical implications of delayed hypoparathyroidism on postoperative day 2 (POD-2) after total thyroidectomy in patients with papillary thyroid carcinoma.

METHODS

This study included 410 patients with normal serum intact parathyroid hormone (iPTH) and calcium levels on postoperative day 1 (POD-1) who were classified into 2 groups according to the presence or absence of delayed hypoparathyroidism on POD-2.

RESULTS

Of the 410 patients, 98 experienced delayed hypoparathyroidism on POD-2 (23.9%). The significant risk factors for delayed hypoparathyroidism on POD-2 included female gender, age older than 45 years, central lymph node dissection, increased number of excised lymph nodes, and low POD-1 versus preoperative iPTH ratios. Additionally, delayed hypoparathyroidism on POD-2 was found to be a significant risk factor for hypocalcemia on POD-2 and permanent hypoparathyroidism.

CONCLUSION

Prophylactic calcium supplementation and long-term surveillance for permanent hypoparathyroidism should be considered in patients with risk factors for delayed hypoparathyroidism on POD-2.

ABBREVIATIONS

CI = confidence interval; iPTH = intact parathyroid hormone; OR = odds ratio; POD-1 = postoperative day 1; POD-2 = postoperative day 2; PTC = papillary thyroid carcinoma; ROC = receiver operating characteristic.

Predicting Postthyroidectomy Hypocalcemia: Improving Predictive Ability of Parathyroid Hormone Level

We performed a retrospective study of our large patient cohort aiming to examine the ability to predict postthyroidectomy hypocalcemia. A retrospective review of patients who underwent total or near-total thyroidectomy at our institution between 2008 and 2018 was performed. Postoperative hypocalcemia was defined as Ca level <8.0 mg/dL (reference range: 8.9–10.1 mg/dL) within 30 days of operation. Logistic regression was used to develop models for prediction of the occurrence of postoperative hypocalcemia. Inclusion criteria were met by 1463 patients. Hypocalcemia was documented in 223 patients (15%). Models based on parathyroid hormone (PTH) levels alone had an associated receiver operator characteristic with an areas under the curve (AUC) of 0.79. There was an inverse relationship between time of measurement and PTH levels within the first two hours after thyroidectomy ( P < 0.01). When measured two to six hours after closure, the predictive ability of PTH compared favorably (AUC = 0.82) with either earlier (within the first two hours after closure, AUC = 0.79) or later measurement (6–24 hours after closure, AUC = 0.77). When measured between two and six hours postoperatively, PTH < 19 pg/mL had a sensitivity of 90 per cent and negative predictive value of 96 per cent for postoperative hypocalcemia. The model that included the PTH level, concurrently measured total blood calcium level, and time of measurement had an improved predictive ability with an AUC of 0.87. PTH level of 19 pg/mL measured two to six hours after thyroidectomy had a sensitivity of 90 per cent and a negative predictive value of 96 per cent in our cohort. The model including postoperative PTH level, calcium level, and time of measurement may further improve the ability to predict postthyroidectomy hypocalcemia.

Performance of a dual-component molecular assay in cytologically indeterminate thyroid nodules

PURPOSE

Deciding whether patients with a cytologically indeterminate thyroid nodule should be referred for surgery or for active surveillance is an important challenge for clinicians. The aim of this study was to evaluate the performance of a novel dual-component molecular assay as an ancillary molecular method for resolving indeterminate thyroid nodule cytology.

METHODS

We selected 156 thyroid nodules from those that had undergone fine-needle aspiration processed by liquid-based cytology and surgical resection between June 2016 and December 2017. The sample set included 63 nodules cytologically classified as indeterminate, and 93 other nodules randomly selected from those with non-diagnostic, benign, suspicious, or malignant cytology. Nucleic acids from each nodule were subjected to next-generation sequencing analysis for mutation detection in 23 genes and to digital polymerase chain reaction (PCR) evaluation for miR-146b-5p expression levels.

RESULTS

Used alone, mutation analysis in the indeterminate subset (cancer prevalence: 22.5%) displayed high sensitivity (89%) and NPV (96%). In contrast, the miR-146b-5p assay offered high specificity (93%) and PPV (93%). Combined use of both analyses improved panel performance by eliminating false-negative results.

CONCLUSIONS

These preliminary data suggest that a dual-component molecular test can increase the diagnostic accuracy of thyroid cytology alone by reducing the number of nodules that will be classified as indeterminate and increasing those that can be reliably classified as benign. If these findings are confirmed, this test can be considered for use in clinical practice and is expected to reduce diagnostic surgery and health care costs, and to improve patient quality of life.

[Modern thyroid surgery - the surgeon's endocrine-surgical understanding and his responsibility for the extent of surgery and complication rate]

Die hohe Qualität der Schilddrüsenchirurgie impliziert ein endokrin-chirurgisches Verständnis des Operateurs mit dem Ziel einer bestmöglichen Ergebnisqualität. Das beinhaltet ein befundadäquates Resektionsausmaß und eine möglichst niedrige Komplikationsrate. Der Chirurg sollte frühzeitig in die Operationsindikation eingebunden sein und auch selbst die Diagnostik, speziell den Schilddrüsen- und Halslymphknotenultraschall, sowie die Interpretation der Schnittbild- und nuklearmedizinischen Verfahren beherrschen. Im Besonderen sollte er über zeitgemäße Radikalitätsprinzipien in der Chirurgie Bescheid wissen.

Bei der gutartigen Struma ist eine individualisierte Operationsstrategie anzuwenden: Solitärknoten können auch einer gewebeschonenden Knotenresektion unterzogen werden. Bei multinodulärer Knotenstruma ist nicht zwingend eine totale Thyreoidektomie notwendig, die Vermeidung eines permanenten Hypoparathyreoidismus hat Priorität. Bei Rezidivstrumen ist oft die einseitige Operation des dominanten Befundes zu bevorzugen. Auch besteht zunehmend der Trend, die Indikation zur Entfernung der Schilddrüsenlappen seitengetrennt zu stellen. Die Basedow Struma erfordert eine Thyreoidektomie. Auch die hypertrophe Thyreoiditis Hashimoto kann eine Operationsindikation darstellen.

Die Radikalitätsprinzipien bei maligner Struma haben sich ebenfalls deutlich gewandelt als auch die strenge Indikation zur Radiojodtherapie. Das gilt speziell für papilläre Mikrokarzinome und minimal invasive follikuläre Tumortypen. Selbst bei medullären Schilddrüsenkarzinom stehen die Radikalitätsprinzipien im Hinblick auf synchrone oder metachrone laterale Halsdissektion in Diskussion.

Der Hypoparathyreoidismus stellt derzeit das Hauptproblem in der radikalen Schilddrüsenchirurgie dar. Recurrensparese und Nachblutung sind durch die subtile Operationstechnik selten geworden. Spezielle extrazervikale Operationszugänge sind nach wie vor in der Erprobungsphase und unter strengen Studienbestimmungen nur Zentren vorbehalten. Die Radiofrequenzablation stellt für gewisse Läsionen wie Zysten und autonome Adenome bei chirurgischer Kontraindikation ein alternatives Ablationsverfahren dar.

[Hypoparathyroidism - un underestimated problem?]

BACKGROUND

Hypoparathyroidism is a rare and disabilitating disorder characterized by hypocalcemia and low parathyroid hormone levels. Most of the cases occur as a result of the removal of parathyroid glands or damage to the glands during neck surgery. More rare causes include nonsurgical causes such as autoimmune or genetic diseases.

METHOD

In this review, a panel of experts presents the current state of diagnosis and therapy of hypoparathyroidism and explains practical aspects of caring for the affected patients.

RESULTS

Common signs and symptoms are abnormal sensations and increased excitability in the lower limbs, paresthesia of perioral areas and nocturnal leg cramps. Renal complications frequently occur, but also basal ganglia calcification. Treatment consists of administration of vitamin D analogs in combination with 0.5-1.0 g calcium daily. An adjunctive treatment with the in April 2017 approved recombinant human parathyroid hormone (1-84) is an option for patients whose hypoparathyroidism is difficult to control by conventional treatment alone. Initially and after dose changes follow-up controls should be performed at least every 2 weeks, in well-controlled patients or in the case of chronic progression every 3-6 months.

Role of Ca²⁺ in Inhibiting Ischemia-Induced Apoptosis of Parathyroid Gland Cells in New Zealand White Rabbits

Background

Hypoparathyroidism is a common complication after thyroidectomy. Calcium supplementation can relieve these symptoms, but it is not clear whether it can protect the parathyroid glands. This study aimed to verify whether Ca²⁺ inhibits the apoptosis of parathyroid cells following ischemic injury.

Material/Methods

A rabbit model of parathyroid gland ischemic injury was established. The blood calcium concentrations were measured by colorimetry. The parathyroid hormone (PTH) levels were measured by enzyme-linked immunosorbent assay (ELISA). The parathyroid tissues were observed by hematoxylin and eosin (H&E) staining and the TdT-mediated dUTP nick-end labeling (TUNEL) assay. Western blotting was used to quantify the levels of the following proteins: caspase-3 and p38 MAP Kinase (p38 MAPK).

Results

This study demonstrates that apoptosis can be a part of the pathological changes associated with parathyroid ischemic injury. Calcium supplementation inhibited the apoptosis of parathyroid cells following ischemic injury. There were no significant differences among the serum calcium levels from the Sham operation (Sham), the Control group (CG), or the Calcium supplementation group (CSG) after 24 h, 72 h, and 168 h of treatment. PTH levels in the CG were significantly higher than in the CSG at 24 h and 72 h after treatments. The apoptosis rate of parathyroid cells from rabbits in the CSG was significantly lower than that of those from rabbits in the CG at 24 h and 72 h after the treatment. Calcium supplementation inhibited p38 MAPK and caspase-3 expression.

Conclusions

This study demonstrates that calcium supplementation inhibited the apoptosis of parathyroid cells following ischemic injury.

Postoperative Hypoparathyroidism: Prognosis, Prevention, and Treatment (Review)

This review summarizes the results of studies concerning the problem of post-surgical hypoparathyroidism, a common complication of thyroid gland surgery, decreasing the quality of life in patients and, in some cases, leading to disability. A search for publications was carried out in electronic databases Web of Science, Scopus, Academic Search Complete (EBSCO), eLIBRARY, using keywords. The search depth was 7-10 years. Prevalence of post-surgical hypoparathyroidism was evaluated, the pathogenetic causes of the disease development, its clinical forms, methods of diagnosis and treatment were studied. It has been found that there is no single algorithm for analyzing the prognostic factors for the development of this pathological condition. It is emphasized that drug therapy of post-surgical hypoparathyroidism has a number of adverse effects. Therefore, the issues of prevention and surgical correction are of particular relevance. However, controversial opinions of contemporary authors about their clinical effectiveness determine the scientific and practical significance of further research on these issues.

Change of surgical strategy for Graves' disease from subtotal thyroidectomy to total thyroidectomy: a single institutional experience

The extent of thyroidectomy in Graves' disease remains controversial. In our institution, long-term euthyroidism without thyroxin replacement therapy has been the aim, and it has long been the standard surgical procedure used to treat Graves' disease in many institutions, including our hospital. Based our several clinical studies, it was concluded that subtotal thyroidectomy is not suitable as a standard surgical procedure for the treatment of Graves' disease. In 2009, the surgical strategy for Graves' disease was changed from subtotal thyroidectomy to total thyroidectomy in our hospital. In this study, how surgical complications have changed after this modification was examined. The subjects were 1,476 patients with Graves' disease treated by thyroidectomy between 2006 and 2014. There were 1,119 females and 357 males with a median age of 39 years. A total of 660 patients underwent bilateral subtotal thyroidectomy (ST group), and 816 patients underwent total thyroidectomy (TT group). Both transient hypocalcemia and prolonged hypocalcemia were observed significantly more frequently in the TT group than in the ST group (p < 0.001). Total thyroidectomy was identified as risk factors for prolonged hypocalcemia on multivariate analysis. In conclusion, total thyroidectomy is a reliable and effective therapy for controlling hyperthyroidism in terms of controlling of hyperthyroidism. However, it should be noted that total thyroidectomy resulted in increased rate of prolonged hypocalcemia. Surgeons should try to reduce the surgical complication rate as much as possible.

Hypocalcemia after thyroidectomy: iPTH levels and iPTH decline are predictive? Retrospective cohort study

Background

Hypocalcemia is the most common complication of thyroid surgery. The aim of this study was to determine the early predictive factors of postoperative hypocalcemia and to analyze their efficiency.

Methods

We performed a retrospective study of 345 consecutive patients who underwent total thyroidectomy at the Endocrine Surgery Department (Policlinico G. Rodolico Hospital of Catania) between January 2011 and November 2013. We measured serum intact parathormone (iPTH) levels preoperatively and 4 h after surgery. The threshold values of hypocalcemia for iPTH levels and iPTH relative decline were obtained by receiver operating curves (ROC) analysis.

Results

The incidence of hypocalcemia was 32.2% (111 of 345 patients). Our statistical analysis revealed that hypocalcemia rate was strongly correlated with the lower iPTH values and greater iPTH decline (P < 0.001). The threshold enabling prediction of hypocalcemia were 12,5 pg/mL for iPTH and 55,7% for relative iPTH decline. Patients with iPTH <12,5 pg/mL developed hypocalcemia in 58.6% of cases while those with iPTH ≥12,5 pg/dl in 18.8%. Among 175 patients with iPTH relative decline greater than 55,7% hypocalcemia was diagnosed in 91 cases (52%), while other 170 patients with iPTH relative decline less than 55,7% developed hypocalcemia only in 20 cases (11,7%).

Conclusions

The decreased iPTH levels and increased iPTH relative decline resulted to be an accurate predictive factors of postoperative hypocalcemia. The early administration of Calcium and vitamin D in the high-risk patients should be put on in order to prevent the symptoms of hypocalcemia and to reduce the costs and duration of hospitalization.

•

Predictive factors of postoperative hypocalcemia.

•

Retrospective study of 345 patients.

•

The threshold were iPTH 12,5 ng/L and iPTH decline 55,7%.

Mortality in patients with permanent hypoparathyroidism after total thyroidectomy

BACKGROUND

Permanent hypoparathyroidism remains the most common adverse outcome after total thyroidectomy, but long-term effects of hypoparathyroidism are unknown. The aim was to investigate mortality in patients with permanent hypoparathyroidism after total thyroidectomy.

METHODS

Data from the Scandinavian Quality Register for Thyroid, Parathyroid and Adrenal Surgery were linked with the Swedish National Prescription Register for Pharmaceuticals and the Swedish National Inpatient Register. Patients who underwent total thyroidectomy between 1 July 2005 and 30 June 2014 for benign thyroid disease, and who used active vitamin D for at least 6 months after surgery, were classified as having permanent hypoparathyroidism and included in the study cohort. Risk of death was assessed using Cox regression analysis, adjusting for age, sex, thyrotoxicosis and co-morbidity.

RESULTS

There were 4899 patients, with a mean(s.d.) age of 46·3(15·8) years; 83·1 per cent were women, and 2932 patients (59·8 per cent) had thyrotoxicosis. In all, 246 patients (5·2 per cent) were classified as having permanent hypoparathyroidism. Mean(s.d.) follow-up was 4·4(2·4) years, and 109 patients (2·2 per cent) died during follow-up. Compared with patients without permanent hypoparathyroidism, the risk of death was significantly higher among patients with permanent hypoparathyroidism after total thyroidectomy (adjusted hazard ratio 2·09, 95 per cent c.i. 1·04 to 4·20).

CONCLUSION

Permanent hypoparathyroidism after total thyroidectomy for benign disease is common and associated with an increased risk of death.

How many parathyroid glands can be identified during thyroidectomy?: Evidence-based data for medical experts

Background

The purpose of this study is to provide guidance for medical experts regarding malpractice claims on permanent hypoparathyroidism by analyzing the number of parathyroid glands (PGs) identified during thyroidectomy and the clinical outcome.

Methods

Parathyroid findings were documented in a standardized protocol for 357 patients undergoing thyroidectomy and treated by a single specialized surgeon. The resected thyroid was routinely dissected for accidentally removed PGs with consecutive autotransplantation and the pathological report also described unintentionally resected PGs. Follow-up was performed for 6 months.

Results

The mean number of identified PGs was 2.28. No PGs were found in 20 (5.6%), one in 56 (15.7%), two in 126 (35.3%), three in 114 (31.9%), and four in 41 (11.5%) cases. One patient (0.28%) had manifest permanent hypoparathyroidism, while ten patients (2.8%) had latent permanent hypoparathyroidism (hypocalcemia and normoparathyroidism). The risk factors identified for postoperative hypoparathyroidism were an increasing number of visualized PGs, autotransplantation, central neck dissection, and PGs in the histopathological work-up. For permanent hypoparathyroidism, PGs in the histology examination and neck dissection were significant, but the number of identified PGs was not.

Conclusion

Even an experienced surgeon is not always able to find all four PGs during thyroidectomy and occasionally identifies none. Rather than focusing on identifying a minimum number of PGs, it is more important not to miss them in risky positions. A documented awareness of PGs, i. e., knowledge of variable parathyroid positions and their saving, is a prerequisite for surgical quality and to protect surgeons from claims.

Cost-effectiveness of lobectomy versus genetic testing (Afirma®) for indeterminate thyroid nodules: Considering the costs of surveillance

BACKGROUND

We evaluated whether diagnostic thyroidectomy for indeterminate thyroid nodules would be more cost-effective than genetic testing after including the costs of long-term surveillance.

METHODS

We used a Markov decision model to estimate the cost-effectiveness of thyroid lobectomy versus genetic testing (Afirma®) for evaluation of indeterminate (Bethesda 3-4) thyroid nodules. The base case was a 40-year-old woman with a 1-cm indeterminate nodule. Probabilities and estimates of utilities were obtained from the literature. Cost estimates were based on Medicare reimbursements with a 3% discount rate for costs and quality-adjusted life-years.

RESULTS

During a 5-year period after the diagnosis of indeterminate thyroid nodules, lobectomy was less costly and more effective than Afirma® (lobectomy: $6,100; 4.50 quality-adjusted life- years vs Afirma®: $9,400; 4.47 quality-adjusted life-years). Only in 253 of 10,000 simulations (2.5%) did Afirma® show a net benefit at a cost-effectiveness threshold of $100,000 per quality- adjusted life-years. There was only a 0.3% probability of Afirma® being cost saving and a 14.9% probability of improving quality-adjusted life-years.

CONCLUSIONS

Our base case estimate suggests that diagnostic lobectomy dominates genetic testing as a strategy for ruling out malignancy of indeterminate thyroid nodules. These results, however, were highly sensitive to estimates of utilities after lobectomy and living under surveillance after Afirma®.

Morbidity of central neck dissection for papillary thyroid cancer

Thyroid cancer has a very well-known propensity for nodal involvement, either in the central and lateral neck compartments. Neck dissection addressing the central compartment may be performed with an elective or therapeutic intent, the former concomitantly to a thyroidectomy whereas the latter may be accomplished also as a revision procedure for recurrent disease. In this paper complications of central compartment neck dissection will be described, analyzing separately primary and revision procedures.

Can Parathormon Levels after Ipsilateral Lobectomy Predict Postoperative Hypocalcemia in Patients Undergoing Total Thyroidectomy?

The purpose of this study was to investigate the relationship between the serum parathormone (PTH) levels measured after completion of hemithyroidectomy on the first side during total thyroidectomy and the postoperative hypocalcemia. The patients were divided into two groups, as those who demonstrated a decrease in PTH levels measured after completion of hemithyroidectomy of the first side (Group 1, n = 43) and those who did not demonstrate a decrease in PTH levels (Group 2, n = 24). The serum PTH levels were measured just before the incision (PTHi), when the hemithyroidectomy stage had been completed (PTHht), at the end of the operation (PTHtt), and at the postoperative 24th hour (PTH24hr). The serum total calcium (Ca21) levels were also measured. The median percentage differences in PTHtt levels based on basal PTHi levels of Groups 1 and 2 were -60.6 and -15.7 per cent, respectively, P = 0.001. The frequency of postoperative biochemical hypocalcemia was higher in Group 1, P < 0.05. It was determined that a 10 per cent or higher decrease in PTHht levels in Group 1 could predict biochemical hypocalcemia at the postoperative 24th hour. In conclusions, postoperative hypocalcemia is seen more frequent in patients with a decrease of PTHht during total thyroidectomy. A decrease of 10 per cent in PTHht levels measured after ipsilateral lobectomy and a 62 per cent or higher decrease in PTHtt levels measured in the end of the total thyroidectomy could be helpful for prediction of postoperative hypocalcemia in these patients.

Preoperative ultrasound-guided carbon nanoparticles localization for metastatic lymph nodes in papillary thyroid carcinoma during reoperation: A retrospective cohort study

Due to the damaged anatomical structure and a large amount of fibrous and scar tissues in the surgical field, reoperation of papillary thyroid carcinoma is difficult. This study introduces a new method of locating metastatic lymph nodes during reoperation and evaluates the effectiveness and safety of the preoperative ultrasound-guided carbon nanoparticles (CNs) localization. This retrospective cohort study enrolled 52 patients who were diagnosed with lymph node metastasis by histopathology and underwent reoperation from October 2015 to February 2016. The modified radical neck dissection or selective neck node dissection was performed. A total of 26 patients underwent preoperative ultrasound-guided CNs injection, and other 26 patients did not. Tolerance, the result of injection, the number of resected metastatic lymph nodes, and postoperative complications were recorded and analyzed. In CNs group, 102 suspicious nonpalpable lesions in 26 patients were injected with CNs, and 99 of the 102 lesions were successfully identified by surgeon in the reoperation. The positive rate of resected lymph nodes in total, in the central compartment, and in the lateral compartment were 31.6%, 31.2%, and 32.8%, respectively, which was significantly higher than that in the control group (P < 0.001, P < 0.001, and P = 0.041). In addition, the positive rates of levels III, IV, and V in the CNs group were 35.6%, 21.9%, and 30.5%, respectively, which was significantly higher than that in the control group (P < 0.001, P = 0.005, and P = 0.01). In additional, in the CNs group, the rate of temporary hypoparathyroidism was significantly lower compared with the control group (0% vs 26.9%, P = 0.021). Preoperative ultrasound-guided CNs injection is a safe and effective method for localization of the metastatic lymph nodes during reoperation.

The Preservation and Autotransplantation of the Parathyroid Glands in Total Thyroidectomy in Patients With Thyroid Cancer—A Strategy for Avoiding Permanent Hypoparathyroidism

Hypoparathyroidism is a complication that occurs after total thyroidectomy (TT) in patients with thyroid cancer. We tried to determine a strategy for avoiding permanent hypoparathyroidism. A total of 42 patients underwent TT for thyroid cancer between April 2009 and March 2014. One or more parathyroid glands (PGs) could be macroscopically preserved in all of the patients. First, we evaluated the association between the number of PGs that were macroscopically preserved and the postoperative course in 28 patients without autotransplantation. The number of preserved PGs was not associated with postoperative tetany or the serum levels of calcium or phosphorous on postoperative day 1, or the proportion of patients who needed to take calcium supplements or a vitamin D analog. However, only the patients with a single preserved PG required calcium supplementation for longer than 1 year (33.3%, P &lt; 0.05). Next, we compared the clinical course with PG autotransplantation in 16 patients in whom a single PG was preserved. Although the result was not statistically significant, only the patients without autotransplantation required calcium supplementation for longer than 1 year. To avoid permanent hypoparathyroidism after TT, it should be essential to preserve at least 2 PGs or to preserve 1 PG and perform autotransplantation.

Paraneoplastic hypocalcemia-induced heart failure in advanced breast cancer: A case report and literature review

Hypocalcemia is an uncommon clinical symptom of patients with malignant tumors, and a number of factors may be involved in its development. The present study describes the case of a 67-year-old Caucasian female, presenting with severe refractory hypocalcemia and heart failure. The patient was subsequently diagnosed with breast cancer and bone metastases. The paraneoplastic origin of the syndrome was confirmed by its complete resolution once the tumor responded to specific antineoplastic treatments, comprising weekly paclitaxel and aromatase inhibitor administration. The present case report suggested the need for greater awareness of the possibility of paraneoplastic hypocalcemia in breast cancer patients, and suggested that this condition may also contribute to the occurrence of heart failure. The mechanisms potentially responsible for this event were discussed and a brief review of the literature presented.

Perioperative kinetics of parathyroid hormone in unilateral, primary thyroid surgery

Dysfunction of the parathyroid glands is an important cause of complications after thyroid surgery. Intraoperative monitoring of the function of the parathyroid glands can be performed using parathyroid hormone (PTH) kinetics. Unilateral thyroid surgery is associated with a decreased risk for postoperative hypocalcemia (POH) and permanent hypoparathyroidism (PEH). We focused on unilateral thyroid surgery by monitoring the functionality of the parathyroid glands and comparing the perioperative PTH kinetics of patients with and without POH. In a prospective study, 143 patients scheduled for unilateral thyroid surgery underwent monitoring of perioperative changes in serum PTH and serum calcium levels, and of clinical symptoms of hypocalcemia. The rates of POH and PEH were 18.2 and 0%, respectively. In patients without POH, PTH significantly increased from the time of skin incision to the end of the operation and after the operation (20.1 pg/ml, IQR 15.5-26.8 vs. 21.4 pg/ml, IQR 16.4-29.5; p=0.005), which was not the case in patients who developed POH. In a multivariate analysis of predictive factors for POH, two parameters became significant, namely female gender (odds ratio 6.87, 95% confidence interval 0.92-51.01) and lower initial serum calcium levels (odds ratio 3.54*e(-8), 95% confidence interval 3.63*e(-12); 0.00). The rate of POH was unexpectedly high. Rather than intraoperative PTH declines, an unstable balance of factors that influence calcium metabolism likely is the major contributor to POH after unilateral thyroid surgery. There was no case of PEH after unilateral, primary thyroid surgery, which underlines the need for an individualized approach to the extent of resection.

[Risk of hypocalcemia after thyroid surgery]

AIM

To reveal calcium metabolism disorders that frequently occur after thyroid surgery.

MATERIAL AND METHODS

The study included 202 patients who underwent thyroid surgery for different diseases and had normal calcium level in peripheral blood at baseline.

RESULTS

Based on laboratory data postoperative hypocalcemia was diagnosed in 57 (28.8%) patients. It was not always accompanied by clinical symptoms. Clinical picture depended on degree of hypocalcemia. Symptoms was diagnosed more frequently if calcium concentration was less than 2.1 mmol/l. Clinical manifestations were absent in 64.9% of cases on background of hypocalcemia. Incidence of hypocalcemia was higher after thyroidectomy compared to organ-preserving surgery. Symptoms of hypocalcemia occurred after thyroidectomy only. Casual parathyroidectomy does not always cause hypocalcemia. Only in 14% of patients with hypocalcemia excised parathyroid was identified in specimen. At the same time 7.6% of patients with postoperative normocalcaemia also had excised parathyroids in specimens. Symptoms of hypocalcemia does not always occur at 1 day after surgery. They can appear later, for example at 5 days postoperatively and depend on severity of hypocalcemia. Thyroidectomy has high risk of postoperative hypocalcemia with clinical symptoms (19.6%) that is transient in 15.5% of cases and permanent in 4.1% of patients.

Autotransplantation of Inferior Parathyroid glands during central neck dissection for papillary thyroid carcinoma: a retrospective cohort study

INTRODUCTION

The management of inferior parathyroid glands during central neck dissection (CND) for papillary thyroid carcinoma (PTC) remains controversial. Most surgeons preserve inferior parathyroid glands in situ. Autotransplantation is not routinely performed unless devascularization or inadvertent parathyroidectomy occurs. This retrospective study aimed to compare the incidence of postoperative hypoparathyroidism and central neck lymph node (CNLN) recurrence in patients with PTC who underwent inferior parathyroid glands autotransplantation vs preservation in situ.

METHODS

This is a retrospective study which was conducted in a tertiary referral hospital. A total of 477 patients with PTC (pN1) who underwent total thyroidectomy (TT) and bilateral CND with/without lateral neck dissection were included. Patients' demographical characteristics, tumor stage, incidence of hypoparathyroidism, CNLN recurrence and the number of resected CNLN were analyzed.

RESULTS

Three hundred and twenty-one patients underwent inferior parathyroid glands autotransplantation (autotransplantation group). Inferior parathyroid glands were preserved in situ among 156 patients (preservation group). Permanent hypoparathyroidism rate was 0.9% (3/321) versus 3.8% (6/156) respectively (p = 0.028). Mean numbers of resected CNLN were 15 ± 3 (6-23) (autotransplantation group) versus 11 ± 3 (7-21) (preservation group) (p < 0.001). CNLN recurrence rate was 0.3% (1/321) versus 3.8% (6/156) respectively (p = 0.003).

CONCLUSION

Inferior parathyroid glands autotransplantation during CND of PTC (pN1) might reduce permanent hypoparathyroidism and CNLN recurrence. Further study enrolling more patients with long-term follow-up is needed to support this conclusion.

Increased risk of long-term sickness absence, lower rate of return to work, and higher risk of unemployment and disability pensioning for thyroid patients: a Danish register-based cohort study

CONTEXT

Little is known about how thyroid diseases affect work ability.

OBJECTIVE

The objective of this study was to evaluate the risk of work disability for patients with thyroid disease compared with the general population.

DESIGN, SETTING, AND PARTICIPANTS

In a longitudinal register study, outpatients (n = 862) with nontoxic goiter, hyperthyroidism, Graves' orbitopathy (GO), autoimmune hypothyroidism, or other thyroid diseases and their matched controls (n = 7043) were observed in the years 1994-2011 in Danish national registers of social benefits, health, and work characteristics. Cox regression analyses estimated adjusted hazard ratios (HRs) for the first year after diagnosis and subsequent years.

MAIN OUTCOME MEASURES

Transitions between work, long-term sickness absence, unemployment, and disability pension were measured.

RESULTS

Patients differed significantly from the general population with regard to sickness absence, disability pension, return from sickness absence, and unemployment. In the first year after diagnosis, higher risks of sickness absence was seen for GO (HR 6.94) and other hyperthyroid patients (HR 2.08), who also had lower probability of returning from sickness absence (HR 0.62) and higher risk of disability pension (HR 4.15). Patients with autoimmune hypothyroidism showed a lower probability of returning from sickness absence (HR 0.62). In subsequent years, GO patients had significantly higher risk of sickness absence (HR 2.08), lower probability of return from sickness absence (HR 0.51), and unemployment (HR 0.52) and a higher risk of disability pension (HR 4.40). Hyperthyroid patients also had difficulties returning from sickness absence (HR 0.71).

CONCLUSIONS

Thyroid patients' risk of work disability is most pronounced in the first year after diagnosis and attenuates in subsequent years. GO patients have the highest risk of work disability.

Relationship between hypoparathyroidism and the number of parathyroid glands preserved during thyroidectomy

Background

The relationship between the number of parathyroid glands preserved and hypoparathyroidism is not well understood. We sought to determine the number of parathyroid glands that need to be preserved to prevent hypoparathyroidism.

Methods

We analyzed 454 patients who underwent total thyroidectomy for papillary thyroid carcinoma. We analyzed the frequency of hypoparathyroidism according to the number of parathyroid glands preserved.

Results

Incidental parathyroidectomy occurred in 19.8% of the patients; one parathyroid gland in 17.6%, two in 1.5%, and three in 0.7%. Transient hypoparathyroidism was increased when incidental parathyroidectomy occurred (odds ratio 1.83, 95% confidence interval 1.04 to 3.23, P = 0.036) on multivariate regression analysis, but was not influenced by the actual number of parathyroid glands removed. There was no relationship between the number of parathyroid glands preserved and permanent hypoparathyroidism (P = 0.147).

Conclusions

Preservation of all parathyroid glands decreases transient hypoparathyroidism compared with when three or fewer glands are preserved, but does not affect permanent hypoparathyroidism. During total thyroidectomy, preserving at least one parathyroid gland with an intact blood supply appears to be sufficient to prevent permanent hypoparathyroidism when autotransplantation is not performed.

Can a surgeon predict the risk of postoperative hypoparathyroidism during thyroid surgery? A prospective study on self-assessment by experts

BACKGROUND

Thyroid surgery can cause postoperative hypocalcemia (POH) and permanent hypoparathyroidism (PEH). Surgeons implicitly assess the risk and adapt their surgical strategy accordingly.

METHODS

The outcome of this intraoperative decision-making process (the surgeons' ability to predict the risk of POH and PEH on a numerical rating scale and their actual incidence) was studied prospectively in 2,558 consecutive thyroid operations.

RESULTS

POH and PEH occurred in 723 and 64 patients, respectively. In multivariate analysis, the surgeons' risk assessment score was an independent predictive factor for both complications (P < .05). Surgeons' differed significantly (P = .015) in their rates of POH but not of PEH (P = .062). Six and 3 (of 9) surgeons correctly predicted an increased risk of PEH and POH (adjusted odds ratios 1.67 to 2.21 and 1.47 to 12.73), respectively.

CONCLUSION

The risk for hypoparathyroidism can be estimated, but surgeons differ substantially in this ability and in the extent to which this implicit knowledge is translated into lower complication rates.

Left-shifted relation between calcium and parathyroid hormone in Graves' disease

BACKGROUND

Patients with Graves' disease (GD) have disturbances in calcium regulation with manifestations such as postoperative hypocalcemia. We have investigated the thyroid as well as the parathyroid function in detail.

MATERIALS AND METHOD

A series of patients undergoing total thyroidectomy for GD (n = 56) or multinodular goiter (MNG; n = 50) were scrutinized for postoperative hypocalcemia and a need for calcium and/or vitamin D substitution. A citrate-calcium (CiCa) clamp was used in 14 patients and 21 controls to quantify the secretion of PTH in relation to the ionized plasma calcium level. The set point, equal to the plasma-ionized calcium concentration at which 50% of the maximal secretion of PTH is inhibited, as well as other CiCa-related parameters were calculated.

RESULTS

Hypocalcemia was present in 48% of GD and 41.2% of patients with MNG postoperatively. Patients with GD had lower calcium levels, 18% had serum Ca less than 2.00 mmol/L compared with 4.0% in the MNG group (P = .02). A higher degree of GD patients were given parenteral calcium substitution during the hospital stay (3.6% vs 0 %) and oral calcium substitution at discharge (48% vs 10%), although they had normal vitamin D3 levels. The GD group showed a significantly left-shifted set point compared with the normal group on the CiCa clamp, 1.16 mmol/L vs 1.20 mmol/L (P < .001) as well as an increased PTH release to hypocalcemic stimulus. GD patients also show an association between degree of subclinical toxicosis at time of surgery and risk for developing postoperative hypocalcemia.

CONCLUSION

Patients with GD demonstrate dysregulation of the calcium homeostasis by several parameters. GD patients have lower postoperative serum calcium compared with patients with MNG, lower calcium/PTH set point, and a significantly increased release of PTH to hypocalcemic stimulus compared with controls. The CiCa clamp response in GD patients with normal 25-hydroxyvitamin D3 levels mimics that of obese patients in which vitamin D insufficiency has been proposed as an underlying cause.

Total thyroidectomy vs bilateral subtotal thyroidectomy in patients with Graves' diseases: a meta-analysis of randomized clinical trials

BACKGROUND

Conducting total thyroidectomy (TT) or subtotal thyroidectomy (ST) in patients with Graves' disease remains controversial. We performed a meta-analysis based on the published randomized controlled trials to evaluate the complications of TT vs ST.

METHODS

We searched multiple electronic databases for prospective, randomized, controlled trials related to safety and effectiveness of TT vs ST. Relative risk (RR) was estimated with 95% confidence interval (CI) based on an intention-to-treat analysis. We considered the following outcomes: recurrent hyperthyroidism, ophthalmopathy progression, temporary and permanent hypoparathyroidism, temporary and permanent recurrent laryngeal nerve palsy (RLNP) and post-operative bleeding.

RESULTS

Four trials with 674 patients (342 with TT, 332 with ST) were analysed. Although the overall rates of ophthalmopathy progression were similar between TT and ST (RR 0·92, 95% CI = 0·50-1·71; P = 0·80), TT was associated with a significant reduction in recurrent hyperthyroidism (RR 0·14, 95% CI = 0·05-0·41; P < 0·01). The pooled RR of post-operative bleeding for TT was similar to that for ST (RR 0·32, 95% CI = 0·05-1·96; P = 0·22). However, comparing with ST, the RR of temporary hypoparathyroidism was significantly higher for TT (RR 2·66, 95% CI = 1·89-3·73; P < 0·01). There was no significant difference in permanent hypoparathyroidism (RR 2·30, 95% CI = 0·78-6·76; P = 0·13), temporary (RR 1·08, 95% CI = 0·47-2·48; P = 0·85) and permanent RLNP (RR 1·54, 95% CI = 0·41-5·73; P = 0·52) between the two groups.

CONCLUSIONS

With regard to ophthalmopathy progression, post-operative bleeding, permanent hypoparathyroidism, temporary and permanent RLNP, TT is consistent with ST in patients with Graves' disease. However, TT is associated with a reduced incidence of recurrent hyperthyroidism and results in an increase in temporary hypoparathyroidism. Therefore, TT should be proposed for the treatment of Graves' disease.

Intact parathyroid hormone measurement at 24 hours after thyroid surgery as predictor of parathyroid function at long term

BACKGROUND

There is no consensus about the usefulness of postoperative intact parathyroid hormone (iPTH) determination to predict permanent hypoparathyroidism (pHPP). We evaluated the value of calcium (Ca2+) and iPTH concentration at 24 hours after total thyroidectomy (TT) for predicting pHPP.

METHODS

Ca2+ and iPTH levels from 70 consecutive patients who underwent TT were measured at 24 hours and 6 months after TT.

RESULTS

Five patients (7.1%) developed pHPP. An iPTH concentration ≤5.8 pg/mL at 24 hours after TT identified patients at risk for pHPP (sensitivity, 100%; specificity, 81.5%), but it was not accurate enough to predict its development (positive predictive value, 30%). Conversely, an iPTH level >5.8 pg/mL predicted normal parathyroid function at 6 months (negative predictive value, 100%). Compared with iPTH, a postoperative Ca2+ level ≤1.95 mmol/L was 60% sensitive and 78.5% specific to predict pHPP.

CONCLUSIONS

An iPTH concentration >5.8 pg/mL on the first postoperative day rules out pHPP with much better diagnostic accuracy than Ca2+. Postoperative iPTH could be helpful in identifying patients at risk for developing pHPP.

Management of Grave's disease is improved by total thyroidectomy

BACKGROUND

A retrospective analysis was performed on 267 consecutive patients with Graves' disease (GD). The principal aim of this study was to evaluate the risk for recurrence and complications when changing the surgical method from subtotal (ST) to total thyroidectomy (TT).

METHODS

Information from 267 consecutive patients operated on for GD between 2000 and 2006 was collected at Uppsala University Hospital (143) and Falun County Hospital (128). There were 229 women and 38 men. Four patients were operated on twice. A total of 40 STs and 229 TTs were performed. Results were compared to those of a previous cohort from the same hospital, with a majority of STs (157/176) performed from 1980 to 1992.

RESULTS

The risk for relapse of GD was reduced from 20 to 3.3 % after the shift from ST to TT. In terms of surgical complications, 2.2 % demonstrated permanent vocal cord paralysis and 4.5 % had persistent hypocalcemia, not significant when compared to the previous cohort. In spite of TT, there were four recurrences, all due to remnant thyroid tissue high up at the hyoid bone. Changing the surgical method did not affect postoperative progression of dysthyroid ophthalmopathy (DO, 7.0 vs. 7.5 %). There were no differences in outcome with respect to which hospital the patients had their operation.

CONCLUSION

Change from ST to TT dramatically reduced the risk for recurrence of GD without increasing the rate of complications. TT is not more effective than ST in hampering progression of DO as has been advocated by some. Careful surgical dissection up to the hyoid bone is necessary to avoid recurrence.

Do low preoperative vitamin D levels reduce the accuracy of quick parathyroid hormone in predicting postthyroidectomy hypocalcemia?

Background

Although some studies have suggested that low preoperative 25-hydroxyvitamin D (25-OHD) levels may increase the risk of hypocalcemia and decrease the accuracy of single quick parathyroid hormone in predicting hypocalcemia after total thyroidectomy, the literature remains scarce and inconsistent. Our study aimed to address these issues.

Methods

Of the 281 consecutive patients who underwent a total/completion total thyroidectomy, 244 (86.8 %) did not require any oral calcium and/or calcitriol supplements (group 1), while 37 (13.2 %) did (group 2) at hospital discharge. 25-OHD level was checked 1 day before surgery, and postoperative quick parathyroid hormone (PTH) was checked at skin closure (PTH-SC). Postoperative serum calcium was checked regularly. Hypocalcemia was defined by the presence of symptoms or adjusted calcium of <1.90 mmol/L. Significant factors for hypocalcemia were determined by univariate and multivariate analyses. The accuracy of PTH-SC in predicting hypocalcemia was measured by area under a receiver operating characteristic curve (AUC), and the AUC of PTH-SC was compared between patients with preoperative 25-OHD <15 and ≥15 ng/mL via bootstrapping.

Results

Preoperative 25-OHD level was not significantly different between groups 1 and 2 (13.1 vs. 12.5 ng/mL, p = 0.175). After adjusting for other significant factors, PTH-SC (odds ratio 2.49, 95 % confidence interval 1.52–4.07, p < 0.001) and parathyroid autotransplantation (odds ratio 3.23, 95 % confidence interval 1.22–8.60, p = 0.019) were the two independent factors for hypocalcemia. The AUC of PTH-SC was similar between those with 25-OHD <15 and ≥15 ng/mL (0.880 vs. 0.850, p = 0.61)

Conclusions

Low 25-OHD was not a significant factor for hypocalcemia and did not lower the accuracy of quick PTH in predicting postthyroidectomy hypocalcemia.

Complications of central neck dissection in patients with papillary thyroid carcinoma: results of a study on 1087 patients and review of the literature

BACKGROUND

Prophylactic central neck dissection (CND) has been proposed in the treatment of patients affected by papillary thyroid carcinoma (PTC) with clinically negative neck lymph nodes. The procedure allows pathologic staging of lymph nodes of the central compartment and treatment of the micrometastases. Nevertheless, the morbidity that its routine use adds to the total thyroidectomy must be taken into account. The aim of this study was to characterize the morbidity that CND adds to the total thyroidectomy.

METHODS

This was a retrospective study of 1087 patients with PTC and clinically negative neck lymph nodes. Patients were divided into three study groups: Group A, total thyroidectomy; Group B, total thyroidectomy and ipsilateral CND; Group C, total thyroidectomy and bilateral CND. Primary endpoints of the study were evaluated by comparing the rates of transient and permanent recurrent laryngeal nerve (RLN) injury and hypoparathyroidism in the three study groups.

RESULTS

Analysis of data showed no significant differences in the rate of transient (Group A: 3.6%, Group B: 3.9%, and Group C: 5.5%; p=0.404) and permanent (Group A: 1%, Group B: 0.5%, and Group C: 2.3%; p=0.099) RLN injury between the three study groups. Both ipsilateral CND and bilateral CND were associated with a higher rate of transient hypoparathyroidism (Group: A 27.7%, Group B: 36.1%, and Group C: 51.9%; p=0.014; odds ratio [OR]: 1.477; 95% confidence interval [CI]: 1.091-2.001; p<0.001; OR: 2.827; 95% CI: 2.065-3.870, respectively). Bilateral CND had a higher rate of permanent hypoparathyroidism (Group A: 6.3%, Group B: 7%, and Group C: 16.2%; p<0.001; OR: 2.860; 95% CI: 1.725-4.743).

CONCLUSIONS

The increased rates of transient and permanent hypoparathyroidism in our series suggest a critical review of indications for the routine use of prophylactic CND for PTC. Prophylactic CND ipsilateral to the tumor associated with total thyroidectomy may represent an effective strategy for reducing the rate of permanent hypoparathyroidism. Concomitant completion contralateral paratracheal lymph node neck dissection should be performed in presence of lymph node metastasis on intraoperative frozen-section pathology. This approach limits the use of bilateral CND to patients with intraoperative pathological findings of lymph node metastases.