Predictors and risk factors of hypoparathyroidism after total thyroidectomy

Persistent hypocalcemia post total thyroidectomy in a case of Hashimoto's thyroiditis

INTRODUCTION

Thyroidectomy is a surgical procedure commonly employed in the management of thyroid disorders. Complications include, but not limited to, postoperative hypocalcemia. In order to effectively manage hypocalcemia following thyroidectomy, a comprehensive approach is essential.

CASE PRESENTATION

We present an intriguing case of a patient who developed severe transient hypocalcemia that was resistant to conventional therapeutic interventions following a total thyroidectomy.

DISCUSSION

Hypocalcemia post total thyroidectomy is a well-established complication which can lead to devastating consequences. Some of the contributing factors include failure of pre-operative optimization, autoimmune disease, malignancy, and prolonged surgical time. A comprehensive approach to identify the contributors is essential in managing the risk factors associated with hypocalcemia.

CONCLUSION

This case highlights the importance of pre-operative elevation and management as well as the close monitoring and individualized treatment plans for patients at risk for post-thyroidectomy hypocalcemia. The successful management of severe hypocalcemia in this patient involved a multidisciplinary team approach and consideration of alternative treatment options.

Gallic acid pretreatment mitigates parathyroid ischemia-reperfusion injury through signaling pathway modulation

Thyroid surgery often results in ischemia-reperfusion injury (IRI) to the parathyroid glands, yet the mechanisms underlying this and how to ameliorate IRI remain incompletely explored. Our study identifies a polyphenolic herbal extract-gallic acid (GA)-with antioxidative properties against IRI. Through flow cytometry and CCK8 assays, we investigate the protective effects of GA pretreatment on a parathyroid IRI model and decode its potential mechanisms via RNA-seq and bioinformatics analysis. Results reveal increased apoptosis, pronounced G1 phase arrest, and significantly reduced cell proliferation in the hypoxia/reoxygenation group compared to the hypoxia group, which GA pretreatment mitigates. RNA-seq and bioinformatics analysis indicate GA's modulation of various signaling pathways, including IL-17, AMPK, MAPK, transient receptor potential channels, cAMP, and Rap1. In summary, GA pretreatment demonstrates potential in protecting parathyroid cells from IRI by influencing various genes and signaling pathways. These findings offer a promising therapeutic strategy for hypoparathyroidism treatment.

No Change in Complications Following Thyroidectomy Despite Increase in Thyroid Cancer Surgeries: A Meta-Regression Analysis

PURPOSE

The increase in thyroid cancer incidence has inevitably led to an increase in thyroid cancer surgeries. This meta-regression analysis aimed to determine if the rate of post-thyroidectomy complications changes by year.

MATERIALS AND METHODS

PubMed and Embase databases were used to perform a systematic literature search of studies published from January 1, 2005, using the keywords "thyroidectomy" and "complication." A meta-regression was performed for post-thyroidectomy hypocalcemia and bleeding.

RESULTS

This meta-analysis included 25 studies involving 927751 individuals. Through the years of publications in this study, there was no significant difference in the proportion of post-thyroidectomy hypocalcemia and bleeding (p=0.9978, 0.6393).

CONCLUSION

Although the number of thyroid surgeries has recently increased, the incidence of post-thyroidectomy hypocalcemia and bleeding did not significantly increase.

Management of Postthyroidectomy Hypoparathyroidism and Its Effect on Hypocalcemia-Related Complications: A Meta-Analysis

OBJECTIVE

The aim of this Meta-analysis is to evaluate the impact of different treatment strategies for early postoperative hypoparathyroidism on hypocalcemia-related complications and long-term hypoparathyroidism.

DATA SOURCES

Embase.com, MEDLINE, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and the top 100 references of Google Scholar were searched to September 20, 2022.

REVIEW METHODS

Articles reporting on adult patients who underwent total thyroidectomy which specified a treatment strategy for postthyroidectomy hypoparathyroidism were included. Random effect models were applied to obtain pooled proportions and 95% confidence intervals. Primary outcome was the occurrence of major hypocalcemia-related complications. Secondary outcome was long-term hypoparathyroidism.

RESULTS

Sixty-six studies comprising 67 treatment protocols and 51,096 patients were included in this Meta-analysis. In 8 protocols (3806 patients), routine calcium and/or active vitamin D medication was given to all patients directly after thyroidectomy. In 49 protocols (44,012 patients), calcium and/or active vitamin D medication was only given to patients with biochemically proven postthyroidectomy hypoparathyroidism. In 10 protocols (3278 patients), calcium and/or active vitamin D supplementation was only initiated in case of clinical symptoms of hypocalcemia. No patient had a major complication due to postoperative hypocalcemia. The pooled proportion of long-term hypoparathyroidism was 2.4% (95% confidence interval, 1.9-3.0). There was no significant difference in the incidence of long-term hypoparathyroidism between the 3 supplementation groups.

CONCLUSIONS

All treatment strategies for postoperative hypocalcemia prevent major complications of hypocalcemia. The early postoperative treatment protocol for postthyroidectomy hypoparathyroidism does not seem to influence recovery of parathyroid function in the long term.

Impact of Clinico Pathological and Surgical Related Risk Factor in Post Operative Hypoparathyroidism in Total Thyroidectomy Patients

Multiple risk factors have been predicted in post operative hypoparathyroidism in total thyroidectomy patients but none have been clearly defined. Present study aims at evaluating the clinic pathological and surgical impact factors in predicting the risk of post operative hypoparathyroidism in thyroidectomy patients. The study was done in Karpaga Vinayaga Institute of Medical Science and Research Centre where Retrospective prospective cohort study who underwent and undergoing total thyroidectomy with or without central neck dissection for both benign and malignant thyroid disorders during 2014 to 2022 was analyzed. The study has analyzed the various risk factors from clinic pathological and surgical skills of identifying the Inferior thyroid artery at its origin and tracing the branches to the parathyroid gland and evaluating the incidence of hypocalcemia in both study and control groups. Two groups were analyzed during the period 2014 to 2022. The study group was included patients with thyroidectomy where ITA were identified and traced up to the parathyroid gland. They were further classified into category A where both sides ITA were identified and saved, category B where only one side was preserved. In control group, the surgery was done only on basis of capsular dissection and peripheral ligation of vessels close to the gland. Total study participants in our study was 416. The overall prevalence of hypocalcemia in our study was 11.4%. The age, gender and pathological variants were comparable between the two groups. Female preponderance (76%) was seen among both the groups. Among total study subjects who underwent total thyroidectomy 44.8% were having multi nodular goitre, 7.3% toxic goitre, 9.8% follicular adenoma, 30.2% papillary carcinoma and 7.9% follicular carcinoma. In our study benign and malignant thyroid disorders had no significant difference. Prevalence of hypocalcemia among control group 14.5% vs study group 3.8%. We found incidence of hypocalcaemia was comparitively lesser among patients with thyroidectomy alone, than those with unilateral or bilateral CND. Prevalence of hypocalcemia among control group was 33% (45/133) and study group 7% (12/153), when thyroidectomy alone was done. However, with neck dissection in bilateral CND, incidence was 41% (23/56) in study group and 61% (11/18) in control group. In unilateral CND, study and control group had 31% (10/32) and 54% (13/24) which was found to be statistically significant. Parathyroid auto transplantation among the control group (29%) compared to the study group (16%). Bilateral neck dissection and gross extrathyroidal extension and cases with PTG inadvertent removal posed significant risk factors for hypoparathyroidism. The prevalence of immediate hypocalcemia among Cat A, Cat B and control group were 14%, 20.3% and 37.5% respectively and was statistically significant (P < .0001). Symptomatic and Biochemical hypocalcemia at the end of 1 week among Cat A, Cat B, and control group was 8%, 12%, and 33.6, & 12.9%, 21% and 30% respectively. Whereas transient hypocalcemia reported among these groups was 1.6%, 5% and 14.6%. Permanent hypocalcemia was < 1% in study group and 4% among control group. We observed that permanent hypocalcemia was high among patients with bilateral neck dissection and auto transplanted PTG. There was no significant statistical difference in hypocalcemia (transient or permanent) among study and control group, but the incidence of hypocalcemia had significantly reduced in both study groups when unilateral or bilateral identification of ITA was done compared to control group. Our hypothesis in this study aims at preserving the branches of ITA supplying PTG distally has greater functional preservation of the parathyroid than conventional technique. This technique also helps us maintaining the plane and capsular dissection if done properly. By trying to preserve the ITA surgeons may acquire better meticulous dissection skills and understanding the anatomical variation of vessels around PTG more precisely which improve the surgical outcome in preventing both transient and permanent hypocalcaemia.

Impact of Obesity on Risk of Hypocalcemia After Total Thyroidectomy: Targeted National Surgical Quality Improvement Program Analysis of 16,277 Patients

INTRODUCTION

Hypocalcemia following total thyroidectomy (TT) is common due to postoperative parathyroid dysfunction and vitamin D deficiency. Given the association between obesity and vitamin D deficiency, we sought to correlate body mass index (BMI) with hypocalcemia after TT.

METHODS

Patients undergoing TT between 2016 and 2020 were identified from the American College of Surgeons National Surgical Quality Improvement Program thyroidectomy-targeted database. Univariable and multivariable regressions, stratified by BMI category (normal, overweight, obese), identified factors associated with hypocalcemia prior to discharge, within 30 d, and severe hypocalcemic events (emergent evaluation, intravenous calcium supplementation, or readmission).

RESULTS

Sixteen thousand two hundred seventy seven TT were performed with available BMI data. Three thousand five hundred thirty one (21.7%) patients had normal BMI, 4823 (29.6%) were overweight, and 7772 (47.7%) were obese. Patients with BMI ≥ 25 had decreased risk of hypocalcemia before discharge (9.8% versus 13%, odds ratio [OR] 0.73, P < 0.001), 30 d (8.1% versus 10.4%, OR 0.76, P < 0.001), and severe hypocalcemic events (5.5% versus 6.4%, OR 0.84, P = 0.029) compared to normal BMI patients. On multivariable analysis for normal BMI patients, age < 45 y was a risk factor for hypocalcemia before discharge, 30 d, and severe hypocalcemic events (P < 0.05 for all). Additional risk factors in this group for 30-d hypocalcemia included parathyroid autotransplant and central neck dissection (P < 0.05) and recurrent laryngeal nerve injury for severe hypocalcemic events (P = 0.01).

CONCLUSIONS

Younger patients with BMI < 25 are at an increased risk for hypocalcemia and severe hypocalcemic events after TT. These patients may benefit from preoperative counseling and increased calcium/vitamin D supplementation to reduce prolonged hospitalization and mitigate morbidity.

The use of Zuckerkandl's tubercle as an anatomical landmark in identifying recurrent laryngeal nerve and superior parathyroid gland during total thyroidectomy: a prospective single-surgeon study

Objective

To determine the incidence and characteristics of Zuckerkandl's tubercle (ZT), and its relationship with recurrent laryngeal nerve (RLN) and the superior parathyroid gland (SPG) in the setting of total thyroidectomy.

Methods

A total of 421 patients (mean (min-max) age: 45.6 (18-78) years, 76.2% were females) who had total thyroidectomy were included in this prospective single-surgeon thyroidectomy series study. Patient demographics and thyroidectomy indications (benign and malignant) were recorded in each patient. The presence, grade and laterality of ZT, and its relationship with RLN and SPG were recorded during surgery.

Results

Most of the thyroidectomy indications (69.1%) were related to a malignant disease. The ZT was unrecognizable in 41(9.7%) of 421 patients. In 380 patients with identifiable ZT, the grade 2 (46.3%) ZT was the most common finding. Majority of ZTs (92.9%) were unilaterally located (right-sided: 64.9%; left-sided: 35.1%). In majority of the cases (83.2%), the RLN was found to lie medial to ZT. Overall, SPG was identified in close proximity to ZT in 66.6% of patients (Class 2 [0.5-1 cm from ZT] in 46.6% and Class 3 [<0.5 cm from ZT] in 20.0%). SPG was more likely to be identified in close proximity to ZT when the grade of ZT was higher, which was found to be located 0.5-1 cm from the ZT in 56.9% and 42.7% of grade 2 and grade 3 ZTs, respectively, and <0.5 cm from the ZT in 46.1% of grade 3 ZTs.

Conclusion

In conclusion, this prospective single-surgeon thyroidectomy series study indicates the likelihood of localizing the RLN medial to ZT, and the SPG in close proximity to ZT during total thyroidectomy operations. Hence, the ZT can be used as a reliable and constant landmark to localize both the RLN and the SPG during thyroid surgery, which enables minimizing the risk of iatrogenic injury to RLN, while ensuring a parathyroid-sparing thyroidectomy. The thyroid surgeon should have complete knowledge of thyroid gland anatomy and embryogenesis and should follow a careful and meticulous approach particularly for dissections around larger ZTs, given the increased likelihood of SPG and RLN to be in close proximity.

Preservation of parathyroid glands during thyroid and neck surgery

The parathyroid glands are situated in close proximity to the thyroid gland. They have an important endocrine function maintaining calcium and phosphate homeostasis in the body by the secretion of parathormone (PTH), which is responsible for this function. The parathyroid glands are commonly damaged during thyroid surgeries. This could lead to transient or permanent hypoparathyroidism in 30% of cases. Preservation of the parathyroid glands, is an important and integral part of thyroidectomy and other surgical interventions in the neck. The main principle underlying this is a thorough understanding of parathyroid anatomy in relation to the thyroid gland and other important structures in the area. There can also be significant variation in the anatomical location of the glands. Various techniques and methods have been described for parathyroid preservation. They include intraoperative identification utilizing indocyanine green (ICG) fluorescence, carbon nanoparticles, loupes, and microscopes. The techniques of surgery (meticulous capsular dissection), expertise, central compartment neck dissection, preoperative vitamin D deficiency, extent and type of thyroidectomy are the risk factors associated with damaged thyroids, inadvertent parathyroidectomy and subsequent hypoparathyroidism. Parathyroid Autotransplantation is a treatment option for inadvertent parathyroidectomy. Ultimately, the best way to assure normal parathyroid function is to preserve them in situ intraoperatively undamaged.

A novel computer based risk prediction model for vocal cord palsy before thyroidectomy

BACKGROUND

Thyroidectomy may be performed for clinical indications that include malignancy, benign nodules or cysts suspicious findings on fine needle aspiration (FNA) biopsy, dyspnea from airway compression or dysphagia from cervical esophageal compression, etc. The incidences of vocal cord palsy (VCP) caused by thyroid surgery were reported to range from 3.4% to 7.2% and 0.2% to 0.9% for temporary and permanent vocal fold palsy respectively which is a serious complication of thyroidectomy that is worrisome for patients.

OBJECTIVE

Therefore, it is aimed to determine the patients who have the risk of developing vocal cord palsy before thyroidectomy by using machine learning methods in the study. In this way, the possibility of developing palsy can be reduced by applying appropriate surgical techniques to individuals in the high-risk group.

METHOD

For this aim, 1039 patients with thyroidectomy, between the years 2015 and 2018, have been used from Karadeniz Technical University Medical Faculty Farabi Hospital at the department of general surgery. The clinical risk prediction model was developed using the proposed sampling and random forest classification method on the dataset.

CONCLUSION

As a result, a novel quite a satisfactory prediction model with 100% accuracy was developed for VCP before thyroidectomy. Using this clinical risk prediction model, physicians can be helped to identify patients at high risk of developing post-operative palsy before the operation.

Risk factors for hypocalcemia and correlation between thyroid volume and incidental parathyroidectomy after total thyroidectomy: single center experience

Aim: We aimed to investigate correlation between the effects of age, sex, disease, pathologic diagnosis, parathyroid autotransplantation, presence of parathyroid in the pathology specimen and clinicopathological variables and thyroid volume, postoperative hypocalcemia after bilateral total thyroidectomy. Material and Method: A retrospective study planned in tertiary university hospital on patients undergone bilateral total thyroidectomy and neck dissection when necessary surgery for thyroid pathologies. Minimum calcium values in the postoperative period were recorded as transient or permanent hypocalcemia. The cases were statistically analyzed for the relationship between the volume of the thyroid gland removed and hypocalcemia. The effects of sex, pathological diagnosis, preoperative hyperthyroidism, anatomical retrosternal extension, number of parathyroid glands seen and preserved intraoperatively, parathyroid gland autoimplantation, parathyroid gland removal in the pathological specimen, nerve monitoring, bilateral total thyroidectomy and central and lateral neck dissection were analyzed for postoperative hypocalcemia. Results: Totally 763 patients were included in the study. The mean age of the patients was 50.6 years (SD:12.8) and the sex of 575 (75.4%) patients was female. Hypocalcemia was more common in women than in men (31% vs 17%; p

Surgical tips and techniques to avoid complications of thyroid surgery

Objectives

Surgery of the thyroid takes place in a body part with complicated anatomy and several vital physiologic functions. Thyroidectomy is rarely associated with mortality but can be followed by significant complications, (i.e. hypoparathyroidism, hemorrhage, upper airway obstruction, laryngeal nerve injuries and thyrotoxic storm). This review aims to indicate surgical tips and techniques to sustain a low level of complications.

Content

MEDLINE database (PubMed) platform was used as a search engine and the articles related to the topic were selected using the keywords combination "thyroid surgery and complications".

Summary and Outlook

The most common complication of total thyroidectomy with an occurrence ranging between 0.5 and 65% is hypoparathyroidism. Damage to recurrent laryngeal nerves can be temporary or permanent, unilateral or bilateral; bilateral lesion is associated with severe episodes of breathlessness. Thus, intraoperative monitoring of nerve function is essential to prevent damage. Ιn addition, hematoma formation can lead to breathing difficulties due to airway obstruction; preventive hemostasis during surgery is essential. The surgeon must have a complete anatomical understanding of not only the normal anatomy of the central visceral compartment of the neck, but also the common variations of the laryngeal nerves and parathyroid glands in order to keep the complication rate at a very low level.

Definition and diagnosis of postsurgical hypoparathyroidism after thyroid surgery: meta-analysis

Background

Postsurgical hypoparathyroidism (PH) is the most frequent complication after thyroid surgery. The aim of this systematic review and meta-analysis is to summarize a unifying definition of PH and to elucidate the best possible approach for early detection of PH.

Methods

A systematic review of the literature according to the PICO framework using Embase, PUBMED and the Cochrane library was carried out on 1 December 2021 followed by analysis for risk of bias, data extraction and meta-analysis. All studies addressing the definition of postoperative hypoparathyroidism and/or diagnostic approaches for early detection and diagnosis were included. Case reports, commentaries, non-English articles, book chapters and pilot studies and reviews were excluded.

Results

From 13 704 articles, 188 articles were eligible for inclusion and further analysis. These articles provided heterogeneous definitions of PH. Meta-analysis revealed that postoperative measurements of parathormone (PTH) levels have a higher sensitivity and specificity than intraoperative PTH measurements to predict PH after thyroid surgery. None of the timeframes analysed after surgery within the first postoperative day (POD1) was superior to predict the onset of PH. PTH levels of less than 15 pg/ml and less than 10 pg/ml are both reliable threshold levels to predict the postoperative onset of PH. A relative reduction of mean(s.d.) PTH levels from pre- to postoperative values of 73 (standard deviation 11) per cent may also be predictive for the development of PH. The estimation of calcium levels on POD1 are recommended.

Conclusion

PH is best defined as an undetectable or inappropriately low postoperative PTH level in the context of hypocalcaemia with or without hypocalcaemic symptoms. PTH levels should be measured after surgery within 24 h. Both threshold levels below 10 and 15 pg/ml or relative loss of PTH before/after thyroid surgery are reliable to predict the onset of PH.

Near-Infrared Autofluorescence Imaging in Thyroid Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

This meta-analysis aimed to assess the position of near-infrared autofluorescence (NIRAF) imaging in the recognition and protection of the parathyroid gland (PG) during thyroidectomy.

METHODS

The PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Library databases were searched up to June 2021. The primary outcome was to evaluate the rates of postoperative hypocalcemia, inadvertent PG resection, and autotransplantation of PG when adopting NIRAF imaging compared with standard naked-eye (N-E) surgery.

RESULTS

Eight studies with 2,889 patients were enrolled in the analysis. Our analysis showed that the incidence of transient hypocalcemia was 7.11% (60/844) in the NIRAF group and 22.40% (458/2045) in the N-E group (p < 0.0001) and the rate of transient hypoparathyroidism was 28.31% (126/445) and 33.36% (496/1487) in the NIRAF and N-E groups (p = 0.0008). The rate of inadvertent resection of PGs was 7.65% (55/719) in the NIRAF group and 14.39% (132/917) in the N-E group (p < 0.0001). No significant difference was observed in other indexes including the pooled proportion of permanent hypocalcemia and rate of PG autotransplantation.

CONCLUSIONS

The application of NIRAF imaging in thyroidectomy can help lower the incidence of inadvertent PG resection and reduce the risk of postoperative hypocalcemia and hypoparathyroidism compared with N-E recognition.

Transient Hypocalcemia After Total Thyroidectomy: The Obesity Paradox at Work?

INTRODUCTION

With increasing rates of obesity worldwide, a correlation between high body mass index (BMI) and postoperative morbidity after thyroid surgery remains unclear. Postoperative transient hypocalcemia is common after total thyroidectomy due to interruption of parathyroid function. This study examines the relationship between BMI and hypocalcemia after total thyroidectomy.

MATERIALS AND METHODS

A retrospective review of prospectively collected data for 1135 patients who underwent total thyroidectomy for cancer, multinodular goiter (MNG), or Graves' disease between June 2009 and November 2020 at a single institution was performed. BMI groups followed the World Health Organization classification. Hypocalcemia was defined as serum calcium ≤8 mg/dL. Calcium levels measured on postoperative day 0 and the following morning were compared between the BMI groups.

RESULTS

Of 1135 total thyroidectomy patients, 85% were women. The mean age and standard deviation of patients was 49 (± 13) y, with most of Hispanic origin (64%). Overall, 41.5% of patients had cancer, 45% nontoxic MNG, 5.8% toxic MNG, and 12% Graves' disease. Stratified by BMI, 27% of patients were normal, 34% overweight, and 39% obese. Overall, overweight and obese patients experienced less transient hypocalcemia at both time points compared to normal patients postoperatively (P = 0.01 and P = 0.009). Furthermore, overweight and obese patients with Graves' disease experienced less transient hypocalcemia at both time points (P = 0.04 and P = 0.05). There was no statistical difference in other groups.

CONCLUSIONS

A protective role of higher BMI or "obesity paradox" for postoperative hypocalcemia may exist in those obese patients after total thyroidectomy.

Hipocalcemia posterior a tiroidectomía total: Análisis de dosis para suplemento rutinario profiláctico

Introducción. La hipocalcemia es la complicación más frecuente de la tiroidectomía. La profilaxis con calcio/ calcitriol es una alternativa costo-efectiva, sencilla y expedita para disminuir esta situación, sin alterar la función paratiroidea residual. Lo que no está claro es si hay superioridad de una dosis frente a otra, por lo que el objetivo de este estudio fue evaluar el comportamiento entre diferentes esquemas de profilaxis para hipocalcemia. Métodos. Estudio de cohorte retrospectivo de adultos operados en un hospital de cuarto nivel, entre febrero de 2017 y diciembre de 2020. Se calculó la tasa de síntomas, la hipocalcemia e hipercalcemia bioquímica en el control postquirúrgico durante las siguientes dos semanas. Se hizo análisis bivariado y multivariado entre dosis de calcio/ calcitriol, otros factores asociados y los desenlaces mencionados. Resultados. Se incluyeron 967 pacientes. El 10 % presentaron síntomas. No hubo diferencias significativas en el calcio sérico del control posquirúrgico entre los grupos con distintas dosis de calcio. La dosis de carbonato de calcio >3600 mg/día y el calcio en las primeras 24 horas de cirugía se asociaron a la presencia de síntomas. La dosis de calcitriol  <1 mcg/día y el bocio aumentaron el riesgo de hipocalcemia bioquímica, mientras que la dosis de 1,5 mcg/día lo disminuyó. Ninguna variable evaluada se asoció a hipercalcemia bioquímica. Conclusiones. Teniendo en cuenta los resultados observados con las dosis de calcio y calcitriol, sugerimos iniciar la profilaxis con un esquema de 3600 mg/día de carbonato de calcio y 1,5 mcg/día de calcitriol. Sin embargo, esta dosis debe modificarse en situaciones como bocio o calcio sérico temprano anormal, que fueron las variables asociadas a mayor riesgo en nuestro estudio.

Intraoperative Indocyanine Green Angiography of Parathyroid Glands and the Prevention of Post-Thyroidectomy Hypocalcemia

BACKGROUND

We compared the reliability of indocyanine green (ICG) angiography and intraoperative PTH levels for predicting early post-thyroidectomy hypocalcemia.

METHODS

Prospective study of 94 patients (71% women, mean age 53.7 years) undergoing total thyroidectomy. An ICG score of 2 (white) indicated a well-vascularized gland. PTH preoperative levels-PTH postresection levels divided by preoperative PTH × 100 was used to determine the PTH decline percentage. A decrease of at least 62.5% or <17.1 pg/mL in ioPTH was the criterion for predicting hypocalcemia.

RESULTS

At surgery, the four parathyroid glands were identified in 50 (53.2%) patients and <4 glands in 44. Calcium supplements were needed by 22 patients (23.4%) postoperatively, 11 patients in each group of 4 and <4 parathyroid glands identified. The diagnostic accuracy of ICG angiography (0.883, 95% confidence interval [CI] 0.800-0.940) and ioPTH (0.862, 95% CI 0.775-0.92) was similar. When all four parathyroid glands were identified, ICG angiography showed a slightly higher diagnostic accuracy, specificity and positive predictive than ioPTH levels, but when < 4 glands were identified, the ioPTH showed a slightly higher diagnostic accuracy, specificity and positive predictive value. Differences were not statistically significant for any of the comparisons.

CONCLUSIONS

The presence of one well-perfused parathyroid gland (ICG score 2) using ICG angiography or ioPTH decline, measured before and after completion of thyroid surgery, is both reliable methods in prediction of early post-thyroidectomy hypocalcemia independently of the number of glands identified intraoperatively.

Role of the 2018 American Thyroid Association statement on postoperative hypoparathyroidism: a 5-year retrospective study

Background

Definitions of postoperative hypoparathyroidism (hypoPT) have never reached consent until the American Thyroid Association (ATA) statement was released, with new characteristics and challenges.

Methods

Patients with papillary thyroid carcinoma who underwent primary total thyroidectomy between January 2013 and June 2018 were retrospectively enrolled. Symptoms of hypocalcemia and their frequency were stringently followed. Patients were divided into groups according to the ATA statement. Incidence of postoperative hypoPT and serum parathyroid hormone levels accompanied by calcium levels, from 1-day to at least 24-month follow-up.

Results

A total of 1749 patients were included: 458 (26.2%) had transient and 63 (3.6%) had permanent hypoPT. Transient hypoPT was found in 363 (20.7%) patients with biochemical hypoPT, 72 (4.1%) with clinical hypoPT, and 23 (1.3%) with relative hypoPT; permanent hypoPT was detected in 8 (0.5%) patients with biochemical hypoPT, 55 (3.1%) with clinical hypoPT, and none with relative hypoPT. Female sex, age ≥ 55 years, unintentional parathyroid gland resection, and autotransplantation of ≥ 2 parathyroid glands were independent risk factors for transient biochemical hypoPT. Age ≥ 55 years, bilateral central neck dissection, and isthmus tumor location were independent risk factors for transient clinical hypoPT. A postoperative 1-day percentage of parathyroid hormone (PTH) reduction of > 51.1% was an independent risk factor for relative hypoPT (odds ratio, 4.892; 95% confidence interval, 1.653–14.480; P = 0.004). No independent risk factor for permanent hypoPT was found.

Conclusion

ATA diagnostic criteria for postoperative hypoPT are of great value in differentiating patients by hypocalcemia symptoms and choosing corresponding clinical assistance; however, they may underestimate the actual incidence.

Hypoparathyroidism: Consequences, economic impact, and perspectives. A case series and systematic review

BACKGROUND

Postoperative hypoparathyroidism (PH) is the most common complication after total thyroidectomy. Incidence varies from 2% to 83%, depending on the definition.

OBJECTIVE

We performed a systematic review of the literature to determine the medico-economic effects of PH and update understanding of long-term consequences, morbidity, and quality of life related to hypoparathyroidism.

METHODS

We considered relevant articles published between 2000 and 2020 concerning long-term consequences of PH and quality of life. All studies concerning the medico-economic assessment of PH were included. We compared data from 2018 to results in the literature.

RESULTS

A proportion of 64/403 (16.8%) patients presented with transient PH during 2018, and 7/403 (1.7%) had permanent PH. Seven patients needed supplementation with alfacalcidol at 6-month follow-up. Factors predicting the need for alfacalcidol were age <45, thyroidectomy for goiter, and lymph node dissection. Additional therapy costs related to PH were €9781.10, and additional hospital costs were €230,400. We qualitatively synthesized 41 studies. Most were retrospective studies and only a few reported costs. No series assessed direct or indirect costs of postoperative PH.

CONCLUSION

To our knowledge, no previous studies reported the medico-economic impact of PH. Decreasing PH associated with fluorescence usage should be considered, particularly concerning cost-effectiveness.

Selective Parathyroid Autotransplantation During Total Thyroidectomy for Papillary Thyroid Carcinoma: A Cohort Study

Purpose: The relationship between the selective parathyroid gland (PG) autotransplantation and hypoparathyroidism is still not completely clear. The aim was to ascertain whether the number of autotransplanted PGs affected the incidence of hypoparathyroidism and recovery of parathyroid function in the long-term for patients with papillary thyroid carcinoma (PTC). Methods: A retrospective cohort study included all patients with PTC who had underwent primary total thyroidectomy with central neck dissection between January 2013 and December 2017. The patients were divided into three groups (0, 1, and 2 PGs autotransplanted, respectively). Results: Of the 2,477 patients, 634 (25.6%) received no PG autotransplantation, 1,078 (43.5%) and 765 (30.9%) were autotransplanted 1 and 2 PGs, respectively, and the incidence of permanent hypoparathyroidism (>1 year) was 1.7%, 0.7%, and 0.4% (P = 0.0228). Both 1 or 2 PGs autotransplanted increased the incidence of transient biochemical hypoparathyroidism (odds ratio [OR], 1.567; 95% confidence interval [CI], 1.258-1.953; P < 0.0001; OR, 2.983; 95% CI, 2.336-3.810; P < 0.0001, respectively) but reduced the incidence of permanent hypoparathyroidism (OR, 0.373; 95% CI, 0.145-0.958; P = 0.0404; OR, 0.144; 95% CI, 0.037-0.560; P = 0.0052, respectively). Both 1 or 2 PGs autotransplanted did not independently influence the occurrence of hypocalcemia symptoms. Conclusion: Selective parathyroid autotransplantation is less likely to lead to post-operative symptomatic hypocalcemia, although it could lead to a transient decrease in parathyroid hormone. However, in the long run, it is still an effective strategy to preserve parathyroid function.

Identification of Patients at High Risk for Postsurgical Hypoparathyroidism

BACKGROUND/AIM

Postsurgical hypoparathyroidism (PostHypo) is a common complication after total thyroidectomy. We studied the risk factors associated with PostHypo.

PATIENTS AND METHODS

The study included 109 women, (mean age: 50.7±10.75 years), who underwent total thyroidectomy for thyroid diseases.

RESULTS

Based on the development of biochemical hypocalcemia on the first postoperative day following total thyroidectomy, (cCa<8.4 mg/dl), 37 women developed PostHypo and 72 did not. Younger age, a lower preoperative corrected calcium and the presence of parathyroid glands in the specimens were related to the development of PostHypo. Of all patients, 51.4% had a vitamin D deficiency. A parathyroid hormone (PTH) value ≤9.4 pg/ml was 84.9% sensitive and 71.4% specific to predict PostHypo on the 1^st postoperative day. A 50% reduction of the PTH value on the 1^st postoperative day from the preoperative level could identify patients who develop PostHypo with 76% sensitivity and 75% specificity.

CONCLUSION

PTH postoperative measurement and its alteration from the preoperative level can be used to identify patients who are at increased risk to develop PostHypo.

Risks and prediction of postoperative hypoparathyroidism due to thyroid surgery

We aimed to investigate the prevalence of postoperative hypoparathyroidism (PoH), the relevant factors, and predictors of transient or permanent hypoparathyroidism. The files of 352 patients who underwent bilateral total thyroidectomy alone or with central lymph node dissection and/or lateral neck dissection between June 1, 2019, and November 30, 2019, were retrospectively evaluated. Also, calcium and parathyroid hormone levels measured preoperatively and 4–6 h after surgery, follow-up examination results, and time to resolution of transient PoH were recorded. 16.48% (n = 58) of the surgical patients developed transient PoH and 3.98% (n = 14) developed permanent PoH. Length of hospital stay increased in patients who developed PoH (p < 0.001). Transient PoH developed less in patients who underwent parathyroid autotransplantation, while permanent PoH was not detected (p = 0.001). PoH development was not significantly correlated with nodule size as measured by preoperative thyroid ultrasonography (p = 0.944). Patients who had a serum PTH level ≤ 5.95 pmol/L 4–6 h after surgery had a greater risk of developing permanent PoH (OR 134.84, 95% CI 17.25–1053.82). PoH is more common in female gender and is not significantly correlated with nodule size. Parathyroid autotransplantation can prevent the development of PoH.

Risk factors for postoperative hypocalcaemia after thyroidectomy: A systematic review and meta-analysis

Objective

A meta-analysis to investigate the risk factors for postoperative hypocalcaemia after thyroidectomy in adult patients.

Methods

A systematic search of publications in the electronic databases (PubMed®, The Cochrane Library, Web of Science, OVID and Embase®) from inception to June 2020 was conducted. Screening of titles, abstracts and full texts and data extraction were independently performed by two authors. The OR was selected as the pooled estimate.

Results

The analysis included 23 studies. Twelve significant risk factors for postoperative hypocalcaemia were identified: hypoparathyroidism, OR 5.58; total thyroidectomy, OR 3.59; hypomagnesaemia, OR 2.85; preoperative vitamin D deficiency, OR 2.32; female sex, OR 1.49; thyroid malignancy, OR 1.85; thyroiditis, OR 1.48; substernal multinodular goitres, OR 1.70; parathyroidectomy, OR 1.58; central compartment neck dissection, OR 1.17; modified radical neck dissection, OR 1.57; and central neck dissection, OR 1.54.

Conclusions

This meta-analysis provides moderate-to-high quality evidence that the 12 risk factors were predictive of postoperative hypocalcaemia, which should be monitored closely before thyroidectomy.

Does number of autotransplanted parathyroid glands affects postoperative hypoparathyroidism and serum parathyroid hormone levels?

BACKGROUND

To investigate how number of autotransplanted parathyroid glands (PGs) affects the incidence of postoperative hypoparathyroidism and the recovery of parathyroid function.

METHODS

A systematic search was performed in the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. The evaluated indices included the incidence of postoperative transient and permanent hypoparathyroidism and parathyroid hormone (PTH) levels during follow-up.

RESULTS

Twenty articles with 7291 patients were included. A higher incidence of transient hypoparathyroidism was found in the PG autotransplantation group than in the preservation group (odds ratio [OR]: 2.37; 95% confidence interval [CI]: 1.90, 2.96). However, there was no significant difference between the two groups regarding permanent hypoparathyroidism (OR: 1.17; 95% CI: 0.71, 1.91). Parathyroid hormone (PTH) levels in the PG autotransplantation group changed significantly more than the preservation group at postoperative 1-day and 1-month, but became similar at the 6-month, 1-year and 2-year follow-up. Autotransplantation of 2 and 3 PGs demonstrated a higher incidence of transient hypoparathyroidism than 1 PG (OR: 2.09; 95% CI: 1.41, 3.11 and OR: 9.70; 95% CI: 2.11, 44.39, respectively), but no significant difference was observed between the autotransplantation of 3 and 2 PGs (OR: 0.99; 95% CI: 0.03, 29.06). Additionally, the incidence of permanent hypoparathyroidism was not significantly different when different number of PGs was autotransplanted.

CONCLUSIONS

PG autotransplantation is an effective mid- and long-term strategy for the preservation of parathyroid function. Although transient hypoparathyroidism was positively correlated with the number of autotransplanted PGs, no remarkable correlation was observed for permanent hypoparathyroidism.

Surgical strategy when identifying less than four parathyroid glands during total thyroidectomy: a retrospective cohort study

Background

Parathyroid glands protection is still controversial in patients with less than 4 parathyroid glands during thyroidectomy. The aim of this study was to investigate the strategy of parathyroid autotransplantation or in situ preservation in patients with 3 parathyroid glands.

Methods

Consecutive patients who underwent primary total thyroidectomy with bilateral central neck dissection for papillary thyroid carcinoma (PTC) in our center were included retrospectively. Serum calcium and parathyroid hormone (PTH) levels (pg/mL), incidence of hypocalcemia and hypoparathyroidism during 24 months follow-up were compared grouping by the number of parathyroid glands both identified intraoperatively and confirmed postoperatively by pathology.

Results

A total of 1,424 patients were included. Serum PTH and calcium levels were lower and the incidence of hypocalcemia was higher in patients with 3 identified parathyroid glands. When excluding patients with accidental parathyroid resection, the results remained similar. Of the 212 patients with 3 identified parathyroid glands, PTH levels at postoperative 12-month in patients underwent autotransplantation were significantly lower than patients with all parathyroid glands preserved in situ (3.65±1.30 vs. 4.67±1.89, P=0.026).

Conclusions

The parathyroid function was weaker in patients with 3 parathyroid glands than patients with 4 before and after operation. Parathyroid glands preserved all in situ promoted better recovery of postoperative function in patients with 3 identified parathyroid glands.

Vitamin D Insufficiency Predicts Susceptibility of Parathyroid Hormone Reduction after Total Thyroidectomy in Thyroid Cancer Patients

OBJECTIVE

Given its role in the regulation of calcium and PTH levels, vitamin D was presumed as a potential predictor of postoperative hypoparathyroidism. However, the reports about their association were controversial. This study aims to reveal the relationship between preoperative vitamin D and postoperative parathyroid hormone (PTH).

METHODS

A total of 242 papillary thyroid cancer (PTC) patients who underwent total thyroidectomy (TT) during the period from June 2016 to December 2017 at our hospital were enrolled. Patients were divided into two groups, HypoP and Non-HypoP groups, based on postoperative PTH < 15.0 or ≥15.0 pg/mL, and ΔPTH₅₀+ and ΔPTH₅₀- groups, based on postoperative PTH reduction ratio ≥ 50% or <50%. Clinicopathological features and laboratory data were compared between two sets of groups.

RESULTS

Preoperative PTH level was lower in the HypoP group than in the Non-HypoP group (42.83 vs. 47.52 pg/mL, p=0.018). No significant difference of vitamin D insufficiency was found between the HypoP and Non-HypoP groups (80.8% vs. 74.1%, p=0.226). The rate of vitamin D insufficiency was higher in the ΔPTH₅₀+ group than in the ΔPTH₅₀- group (82.6% vs. 68.4%, p=0.010). By multivariate logistic regression analysis, vitamin D insufficiency was an independent predictor of postoperative PTH reduction ratio ≥ 50% (OR = 2.2, p=0.017).

CONCLUSION

Vitamin D insufficiency is not associated with postoperative PTH in PTC patients undergoing TT. However, vitamin D insufficiency is an independent predictor of postoperative PTH reduction ratio.

The impact of operative duration and intraoperative fluid dynamics on postoperative hypocalcemia after total thyroidectomy: a prospective non-randomized study

BACKGROUND

Postoperative hypocalcemia after total thyroidectomy (TT) still remains common. This prospective observation study examined the role of intraoperative time period (IOP) and intravenous fluids (IVF) in transient and permanent (> 6 months) hypocalcemia post-TT.

SUBJECTS AND METHOD

Consecutive patients (n = 328; age = median (IQR); 34 (15) years; M:F = 65:263) with benign or malignant thyroid disease undergoing TT were evaluated for IOP, intraoperative IVF, serum corrected calcium, intact parathormone (iPTH), and 25-hydroxyvitamin D (25OHD) levels at baseline, 48 h, and 6 months post-TT.

RESULTS

The incidence of symptomatic transient and permanent hypocalcemia post-TT was 33.5% and 7.9% respectively. In multivariate logistic regression analysis, the independent risk factors for transient hypocalcemia were IOP (odds ratio: 11.6), 48-h iPTH (4.8), IVF (2.9), hyperthyroidism (2.8), and percent calcium decline (1.07), while 25OHD deficiency increased the risk by 10.5 odds in subset with preoperative hypocalcemia. In receiver operating characteristic analysis, IOP, and IVF strongly predicted transient hypocalcemia with a threshold of 123 min and 1085 mL. Area under the curve, sensitivity, and specificity were 0.883 (95% CI: 0.838-0.928), 88.1%, and 74.4% and 0.883 (0.840-0.926; each P = 0.001), 84.4%, and 74.4% respectively. Serum 48-h calcium < 7.8 mg/dL was the only reliable predictor of permanent hypocalcemia.

CONCLUSION

Operative duration > 123 min and IVF > 1085 mL increased the risk of transient hypocalcemia post-TT manyfold but not permanent hypocalcemia. Routine intraoperative identification, preservation of viable in situ parathyroid glands, and laryngeal nerves increased IOP and rates of transient hypocalcemia but improved long-term outcome.

The Effect of Hypomagnesemia on Refractory Hypocalcemia after Total Thyroidectomy: A Single-Center Prospective Cohort Study

BACKGROUND

Hypomagnesemia is known to impede hypocalcemia correction. This prospective observational study aimed to evaluate the impact of serum magnesium levels on the development of refractory hypocalcemia, which remains a concerning problem after total thyroidectomy (TT).

SUBJECTS AND METHODS

Consecutive subjects (n = 312; mean age = 38.4 [range: 13-83] years; M:F = 62:250) undergoing TT for benign or malignant thyroid diseases were evaluated for serum corrected-calcium (8.4-10.4 mg/dL), magnesium (1.7-2.4 mg/dL), intact parathormone (iPTH), and 25-hydroxycholecalciferol (25OHD) levels preoperatively, at 48-h and 6-month post-TT.

RESULTS

Postoperatively, 98 subjects (31.4%) exhibited transient hypocalcemia, 96 (30.8%) had hypomagnesemia, and 52 (16.7%) had refractory hypocalcemia. Preoperatively, 38 subjects (12.2%) had asymptomatic hypocalcemia and 77 (24.7%) had hypomagnesemia. In multivariate logistic regression analysis, independent risk factors of transient hypocalcemia were hyperthyroidism (odd's ratio [OR]: 5.6), 48-h iPTH (OR: 3.2), 48-h magnesium (OR: 2.7), preoperative 25OHD (OR: 0.96), and preoperative calcium (OR: 0.5; each P < 0.01). In receiver-operating characteristic analysis, percent calcium decline and 48-h magnesium reliably predicted transient hypocalcemia with a threshold of 10.5% and 1.9 mg/dL, respectively. Area under curve, sensitivity, and specificity were 0.822, 82.7%, and 72.9%; and 0.649 (each P < 0.001), 68.4%, and 63.1%, respectively.

CONCLUSION

Serum magnesium below 1.9 mg/dL had 2.7 times higher odds of developing transient hypocalcemia post-TT. Hypomagnesemia and percent calcium decline >10.5% within 48-h post-TT are associated with refractory hypocalcemia, which necessitates correction of both the deficiencies for prompt resolution of symptoms.

Hypocalcemia After Completion Thyroidectomy for Papillary Thyroid Carcinoma

Surgical management of papillary thyroid carcinoma (PTC) includes total thyroidectomy and lobectomy. After lobectomy, a reoperation called completion thyroidectomy is occasionally required. Postoperative hypocalcemia is the most common complication associated with thyroid surgery. Our main goal was to determine if there is a significant difference between the incidence rate of postoperative hypocalcemia in patients who underwent total thyroidectomy for PTC compared with patients who underwent completion thyroidectomy for PTC. Apart from that, we analyzed the following potential predictive factors for the occurrence of hypocalcemia: sex, age, size of tumor, side of tumor, maximum diameter of individual lobe, occult metastasis, and operating surgeon. The study involved 340 patients who underwent surgery for PTC at the Department of ENT and Head and Neck Surgery, Zagreb University Hospital Centre, between February 25, 2013 and January 3, 2016. Postoperative hypocalcemia incidence rates were higher in the total thyroidectomy group than in the completion thyroidectomy group (37.8% and 29.0%, respectively). However, these differences were not statistically significant. Every analyzed potential predictive factor was proven not to have any correlation with postoperative hypocalcemia. This study demonstrated that there was no significant difference between postoperative hypocalcemia rates in patients who underwent completion thyroidectomy compared with patients who underwent total thyroidectomy for PTC.

Hypoparathyroidism

BACKGROUND

Hypoparathyroidism is a rare endocrine disorder characterized by hypocalcemia and low or undetectable levels of parathyroid hormone.

METHODS

This review is an evidence-based summary of hypoparathyroidism in terms of relevant pathophysiological, clinical, and therapeutic concepts.

RESULTS

Many clinical manifestations of hypoparathyroidism are due to the lack of the physiological actions of parathyroid hormone on its 2 major target organs: the skeleton and the kidney. The skeleton is inactive, accruing bone without remodeling it. The kidneys lose the calcium-conserving actions of parathyroid hormone and, thus, excrete a greater fraction of calcium. Biochemical manifestations, besides hypocalcemia and low or undetectable levels of parathyroid hormone, include hyperphosphatemia and low levels of 1,25-dihydroxyvitamin D. Calcifications in the kidney, brain, and other soft tissues are common. Removal of, or damage to, the parathyroid glands at the time of anterior neck surgery is, by far, the most likely etiology. Autoimmune destruction of the parathyroid glands and other genetic causes represent most of the other etiologies. Conventional treatment with calcium and active vitamin D can maintain the serum calcium level but high doses may be required, adding to the risk of long-term soft tissue calcifications. The advent of replacement therapy with recombinant human PTH(1-84) represents a major step in the therapeutics of this disease.

CONCLUSIONS

Advances in our knowledge of hypoparathyroidism have led to greater understanding of the disease itself and our approach to it.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Risk factors and effects of hypocalcemia prior to discharge following thyroidectomy

PURPOSE

To find patient and surgical characteristics associated with hypocalcemia prior to discharge (HPTD) in thyroidectomy patients.

MATERIALS AND METHODS

In a retrospective analysis of the 2016-2017 National Surgical Quality Improvement Program, eligible total thyroidectomy patients were stratified into cohorts based on development of HPTD. We identified demographic and surgical risk factors for the development of hypocalcemia via binary logistic regression and identified the negative sequelae of HPTD utilizing univariate and multivariate methods.

RESULTS

We identified a total of 6519 patients who underwent total thyroidectomy, of which 450 (6.9%) had HPTD. Predictors associated with an increased incidence of HPTD included female sex (OR: 1.737 [95% CI: 1.319-2.288]; p < .001), increased operative time (OR: 1.003 [1.002-1.004]; p < .001), and central neck dissection (OR: 1.484 [1.190-1.850]; p < .001). However, factors that decreased incidence of HPTD included increased age, obesity (OR: 0.648 [0.501-0.837]; p = .001), and the use of vessel sealant devices (VSD) (OR: 0.650 [0.527-0.803]; p < .001). Multivariate analysis further revealed that HPTD independently led to an increased hospitalization length after surgery (B: 0.708 [0.607-0.809]; p < .001) and an increased 30-day readmission rate (OR: 2.429 [1.594-3.704]; p < .001).

CONCLUSION

Obesity, increased age, and intra-operative VSD use were significantly associated with decreased rates of HPTD after total thyroidectomy. Female sex, longer operations, and central neck dissections were associated with HPTD. Delineating risk factors and protective factors for HPTD in total thyroidectomy patients is important as patients with HPTD were found to be at a significantly higher risk for longer post-operative stays, increased odds of 30-day readmission, and increased hypocalcemia-related event.

A Single Parathyroid Hormone Measurement Two Hours after a Thyroidectomy Reliably Predicts Permanent Hypoparathyroidism

INTRODUCTION

Hypoparathyroidism is the most common complication following thyroidectomy, and various algorithms for early detection have been suggested. The aim of this study was to evaluate the predictive value of measuring the parathyroid hormone level 2 h after thyroidectomy and whether determination of the perioperative decline in parathyroid hormone added diagnostic value.

METHODS

Patients subjected to thyroidectomy for benign thyroid disorders were analyzed in (1) a retrospective register-based study (366 consecutive patients treated during 2015-2016) and (2) a prospective observational study (39 patients treated during 2018). Optimal cut-off values for postoperative parathyroid hormone and perioperative decline (%) in parathyroid hormone were determined by receiver operating characteristics and area under the curve. Sensitivity, specificity, positive and negative predictive values were calculated using cross tabulation.

RESULTS

The prevalence of hypoparathyroidism the first day after thyroidectomy was higher among patients treated for hyperthyroidism (30% vs 20%; P = 0.03). The optimal cut-off level for postoperative parathyroid hormone was 1.1 pmol/L (area under the curve = 0.887, 95% confidence interval: 0.839-0.934; positive predictive value: 88%, negative predictive value: 93%) for the entire cohort. When the groups were analyzed separately, the optimal cut-off was 1.05 for the non-hyperfunctioning group and 1.55 pmol/L for the group with hyperthyroidism. Twelve months after thyroidectomy, 3% were defined as having permanent hypoparathyroidism. Measurement of parathyroid hormone decline added diagnostic value for one patient with preoperative parathyroid-hormone-elevation associated with vitamin D deficiency.

CONCLUSION

For patients with vitamin D sufficiency, the diagnostic accuracy of a single measurement of parathyroid hormone 2 h after thyroidectomy is an excellent indicator for predicting transient hypoparathyroidism.

Central Compartment Nodal Bulk: A Predictor of Permanent Postoperative Hypocalcaemia

Central compartment clearance (CCC) for Papillary thyroid cancers (PTC) is one of the factors causing postoperative hypocalcaemia. We aimed to examine determinants of this major sequela. 41 patients treated for PTCs between 2014 and 2016 were studied. Surgical details, tumour and nodal characteristics, incidence of transient, temporary and permanent hypocalcaemia were noted. Central clearance was done bilaterally in 24 (58.5%) cases, ipsilaterally in 17 (41.6%). Central nodes were involved in 26 (63.4%) cases, unilaterally in 15 (36.6%), bilaterally in 11 (26.8%). Transient hypocalcaemia developed in 10 (24.4%) cases, temporary hypocalcaemia in 6 (14.6%) cases, and permanent hypocalcaemia in 2 (4.9%) cases. 17 (41%) patients were symptomatic. 9 (21.9%) patients received intravenous calcium. The only factor consistently associated with development of hypocalcaemia of all patterns, was the presence of matted central compartment nodes (p = 0.021). Matted nodes also related to a longer length of stay (p = 0.04) and requirement of intravenous calcium (p = 0.000). Extent of CCC, nodal yield, nodal positivity, perinodal extension, number of parathyroids identified, gender or pT size were not significantly associated. Symptomatic patients did not necessarily become permanently hypocalcaemic (p = 0.8). Patients requiring intravenous calcium were more likely to take oral calcium after discharge (p = 0.002). Postoperative hypocalcaemia is more likely in cases with bulky involved central nodes where extensive clearance is done. In routine CCC, even if done bilaterally, preservation of parathyroid function is possible. Permanent hypocalcaemia after CCC need not be taken as inevitable.

Parathyroid Hormone Reduction Predicts Transient Hypocalcemia after Total Thyroidectomy: A Single-Center Prospective Study

OBJECTIVE

We performed this study to investigate the risk factors for postoperative hypocalcemia after total thyroidectomy with central lymph node dissection (CLND). Study Design. This was a single-center prospective study based on 176 consecutive patients who underwent total thyroidectomy for papillary thyroid carcinoma. Setting. Patients were recruited between January 2016 and June 2018. Subjects and Methods. Patients who underwent bilateral (n = 155, bilateral group) and ipsilateral CLND (n = 21) after total thyroidectomy were included. The preoperative and postoperative parathyroid hormone (PTH) and calcium levels were detected. The risk factors for transient hypocalcemia were identified using logistic regression analysis and receiver operating characteristic (ROC) curve analysis.

RESULTS

Fifty-one (28.98%) patients developed transient hypocalcemia, and 2 patients (1.14%) developed permanent hypoparathyroidism. There was no difference in the gender ratio or the morbidity of hypocalcemia between the patients who underwent bilateral and ipsilateral CLND. On postoperative day 1, PTH decrease was a risk factor for transient hypocalcemia in the whole cohort (β = 0.043, OR = 1.044, 95% CI 1.023-1.065, p < 0.001), bilateral group (β = 0.042, OR = 1.043, 95% CI 1.022-1.064, p < 0.001), and female patients (β = 0.049, OR = 1.050, 95% CI 1.026-1.075, p < 0.001). Tumor diameter was a risk factor for transient hypocalcemia in female patients (β = 0.499, OR = 1.647, 95% CI 1.003-2.704, p=0.049). The ROC curve analysis illustrated that 65.58%, 71.00%, and 71.00% PTH level reduction had high accuracy in predicting transient hypocalcemia in the whole cohort, bilateral group, and female patients, respectively (AUC = 0.986, 0.987, and 0.987).

CONCLUSION

Asymptomatic female patients with bilateral CLND and a 71.00% PTH level reduction were at a high risk of transient hypocalcemia.

Risk Factors of Incidental Parathyroidectomy and its Relationship with Hypocalcemia after Thyroidectomy: A Retrospective Study

Background: The aim of this study was to determine the incidence of incidental parathyroidectomy, the relationship between incidental parathyroidectomy and postoperative hypocalcemia, and risk factors for incidental parathyroidectomy in patients undergoing thyroid surgery.

Methods: The study was conducted by analyzing the records of patients who underwent thyroid surgery in a tertiary university hospital between January 2012 and December 2017 retrospectively. The risk factors of postoperative hypocalcemia were determined by comparing postoperative Ca values with age, sex, preoperative Ca value, dominant nodule diameter, type of surgery, and histopathological examination of the thyroidectomy material. According to the final pathology results, the patients were divided into two groups - the ones with and without incidental parathyroidectomy. The risk factors for incidental parathyroidectomy were determined by comparing the two groups in terms of age, sex, dominant nodule diameter, type of surgery, and histopathological results (malign/benign).

Results: When the risk factors of postoperative hypocalcemia were examined, female gender, age <28.5 years old, low level of preoperative mean Ca value, and total thyroidectomy were found to be critical risk factors (p<0.05). When the risk factors of incidental parathyroidectomy were examined, total thyroidectomy and thyroid malignancy were found to be important risk factors (p<0.05).

Conclusion: Female gender, age<28.5 years old, low level of preoperative Ca value, and total thyroidectomy were associated with postoperative hypocalcemia, but no relationship was found between incidental parathyroidectomy and postoperative hypocalcemia.

The Impact of Post-thyroidectomy Paresis on Quality of Life in Patients with Nodular Thyroid Disease

Objective

To investigate the impact of postoperative paresis on disease-specific quality of life (DSQoL) after thyroidectomy in patients with benign nodular thyroid disease.

Study Design

Observational study.

Setting

University hospital.

Subjects and Methods

Patients were evaluated before and 3 weeks and 6 months after surgery in an individual prospective cohort study using videolaryngostroboscopy (VLS), voice range profile, voice handicap index (VHI), multidimensional voice program, maximum phonation time (MPT), and auditory perceptual evaluation. Changes in DSQoL were assessed by the Thyroid-specific Patient-Reported Outcome measure. Cohen’s effect size was used to evaluate changes.

Results

Sixty-two patients were included, 55 of whom completed all examinations. Three weeks after surgery, a blinded VLS examination showed signs of paresis of either the recurrent laryngeal nerve or the external branch of the superior laryngeal nerve (RLN/EBSLN) in 13 patients (24%). A paresis corresponded to a 12 ± 28 point increase in VHI ( P = .002) and was associated with a significant 4.3 ± 7.5 semitone decrease in the maximum fundamental frequency ( P < .001) and a 5.3 ± 8.2 dB reduction in maximum intensity. Further, it was associated with a 4.5 ± 11.2 second reduction in MPT ( P = .001) and an increase of 0.40 ± 1.19 in grade, 0.42 ± 1.41 in roughness, and 0.36 ± 1.11 in breathiness. Signs of postoperative RLN/EBSLN paresis correlated with an 11.0-point ( P = .02) poorer improvement in goiter symptoms at both 3 weeks and 6 months after surgery.

Conclusion

Signs of RLN/EBSLN paresis after thyroidectomy were associated with less pronounced improvement in goiter symptoms in patients with thyroid nodular disease. However, thyroidectomy was associated with an overall improved DSQoL by 6 months after surgery.

Determination of risk factors causing hypocalcaemia after thyroid surgery

OBJECTIVE

The most common complication after thyroid surgery is hypocalcaemia and it sometimes leads to problems that are difficult to correct in patients. The present study was aimed to determine the risk factors causing the development of hypocalcaemia after thyroid surgery.

METHODS

818 adult patients were included in the study. The data were recorded by examining the hospital automation system and patient files retrospectively. Patients' demographic characteristics, radiological imaging findings, serum biochemical parameters, extent of the performed surgery, histopathological diagnoses were recorded.

RESULTS

The rate of hypocalcaemia was 28.4% (1.7% permanent). In multivariate analysis: the female gender (p = 0.002), heavier thyroid gland (p = 0.084), substernal location (p = 0.004) and cervical lymph nodes dissection (CLND) (p < 0.001) were found to be significantly. Malignant thyroid pathology (p = 0.006) and total thyroidectomy (p = 0.025) increased the risk of hypocalcaemia significantly in univariate analysis. However, this increase in risk was not found to be statistically significant in regression analysis. Significant statistical result was not found on postoperative hypocalcaemia in terms of advanced age, hyperthyroidism and re-operation. The duration of hospitalization was higher in patients with postoperative hypocalcaemia (m = 2 days) (p < 0.001).

CONCLUSION

In our analyses CLND, female gender, substernal location and heavier thyroid gland was found to be the independent risk factors in the development of postoperative hypocalcaemia. The development of postoperative hypocalcaemia may be predicted and measures may be taken to prevent clinical findings.

Causes and pathophysiology of hypoparathyroidism

Hypoparathyroidism, a disorder characterized by hypocalcemia ensuing from inadequate parathyroid hormone secretion, is a rather rare disorder caused by multiple etiologies. When not caused by inadvertent damage or removal of the parathyroids during neck surgery, it is usually genetically determined. Epidemiological figures of this disease are still scarce and mainly limited to countries where non-anonymous databases are available and to surgical case series. Both the surgical and non-surgical forms pose diagnostic challenges. For surgical hypoparathyroidism, transient forms have to be ruled out even in the long term, in order to avoid unnecessary chronic replacement therapy with calcium and calcitriol. Regarding non-surgical hypoparathyroidism, once referred to as idiopathic, a systematic clinically and genetically-driven approach to define the precise diagnosis have to be pursued. In the case of syndromic hypoparathyroidism, patients have to be screened for associated abnormalities. Autoimmune, non-genetic hypoparathyroidism is still a diagnosis of exclusion, since no specific autoantibodies are specific for this condition.

Prediction of permanent hypoparathyroidism by parathyroid hormone and serum calcium 24 h after thyroidectomy

PURPOSE

To assess the value of 24-hour intact parathyroid hormone (iPTH), serum calcium, and decreases in both were evaluated against preoperative values (iPTH and serum calcium decline) and used to determine the existence of permanent hypoparathyroidism (pHPP) after total thyroidectomy (TT).

MATERIALS AND METHODS

The clinical data of patients who underwent total thyroidectomy in our hospital between September 2014 and July 2015 were retrospectively analyzed.

RESULTS

There were 42 cases with normal parathyroid function, 58 cases with temporary HPP, and 10 cases with pHPP. When iPTH and serum calcium were administered at 24 h after surgery, iPTH decline and calcium decline differed significantly among the three groups above (P < .01). The accuracy and positive predictive value of 24 h iPTH for pHPP were higher than any one of the others. The sensitivity, specificity, false positive rate, and accuracy were 100%, 95%, 33.33%, and 94.45%, respectively. The AUC was 0.982 when 24-hour iPTH was equal to or <3.15 pg/mL. The use of blood calcium equal to or <2.03 mmol/L (8.12 mg/dL) pointed to a diagnosis of pHPP, with a sensitivity of 100%, specificity of 63%, false positive rate of 78.72%, and accuracy of 66.36%.

CONCLUSIONS

Measurement of the postoperative 24-h intact parathyroid hormone and serum calcium concentration can predict the occurrence of permanent hypoparathyroidism and the former is more advantageous. Postoperative 24-h intact parathyroid hormone equal to or <3.15 pg/mL is a reliable index, and it is suitable for the prediction of postoperative permanent hypoparathyroidism.

Hypocalcemic disorders

Calcium is vital for life, and extracellular calcium concentrations must constantly be maintained within a precise concentration range. Low serum calcium (hypocalcemia) occurs in conjunction with multiple disorders and can be life-threatening if severe. Symptoms of acute hypocalcemia include neuromuscular irritability, tetany, and seizures, which are rapidly resolved with intravenous administration of calcium gluconate. However, disorders that lead to chronic hypocalcemia often have more subtle manifestations. Hypoparathyroidism, characterized by impaired secretion of parathyroid hormone (PTH), a key regulatory hormone for maintaining calcium homeostasis, is a classic cause of chronic hypocalcemia. Disorders that disrupt the metabolism of vitamin D can also lead to chronic hypocalcemia, as vitamin D is responsible for increasing the gut absorption of dietary calcium. Treatment and management options for chronic hypocalcemia vary depending on the underlying disorder. For example, in patients with hypoparathyroidism, calcium and vitamin D supplementation must be carefully titrated to avoid symptoms of hypocalcemia while keeping serum calcium in the low-normal range to minimize hypercalciuria, which can lead to renal dysfunction. Management of chronic hypocalcemia requires knowledge of the factors that influence the complex regulatory axes of calcium homeostasis in a given disorder. This chapter discusses common and rare disorders of hypocalcemia, symptoms and workup, and management options including replacement of PTH in hypoparathyroidism.

The timing of parathyroid hormone measurement defines the cut-off values to accurately predict postoperative hypocalcemia: a prospective study

PURPOSE

Serum intact parathyroid hormone (iPTH) level is an early marker of post-thyroidectomy hypocalcemia. However, lack of methodological standardization to define timing and cut-off points of iPTH measurement limit its clinical applicability. Here, we evaluated the relationship between two distinct postoperative time sampling and iPTH accuracy on predicting hypocalcemia.

METHODS

iPTH was measured within 4 h after surgery (iPTH 4 h) and on the morning of the first postoperative day (iPTH 1st PO). Hypocalcemia was defined by levels of total calcium corrected by serum albumin ≤ 8.0 mg/dL and/or by the presence of symptoms. The most accurate iPTH cut-off point for hypocalcemia prediction was established from a ROC curve comparing both time-points.

RESULTS

The study included 101 patients. The mean age was 52.4 ± 12.9 years, 93 were women (92.1%) and 69 patients underwent total thyroidectomy (68.3%). Hypocalcemia occurred in 25 patients (24.8%), of whom 12 were symptomatic. Total thyroidectomy, longer duration of surgery, surgical complications related to parathyroid glands and lower levels of iPTH 4 h and iPTH 1st PO were associated with postoperative hypocalcaemia (all P < 0.05). Using the ROC curve, the optimal cut-off points were 19.55 pg/mL and 14.35 pg/mL for iPTH 4 h and iPTH 1st PO, respectively. The comparison of the AUC showed no significant difference between these two points of evaluation (0.935 vs. 0.940; P = 0.415).

CONCLUSIONS

Serum iPTH levels measured within 4 h or on the first morning after surgery are predictors of postoperative hypocalcemia. Notably, both time-points have the same accuracy to predict postoperative hypocalcemia (with different cutoff points).

[Symptomatic hypocalcemia after thyroidectomy : Prevention by a combination of prophylaxis and risk-adapted substitution]

BACKGROUND

Treatment of hypocalcemia after thyroidectomy consists of an individual substitution, prophylaxis or a daily administration of calcium/vitamin D3.

OBJECTIVE

Does prophylactic therapy combined with a risk-adapted substitution of calcium and vitamin D3 reduce symptomatic hypocalcemia compared to individual substitution?

MATERIAL AND METHODS

After implementation of a new algorithm, patient data were prospectively documented and analyzed compared to a historical patient population. The algorithm consisted of a single prophylactic i. v. administration of calcium (1 g calcium gluconate 10% in 250 ml saline) and a risk-adapted oral administration of calcium and vitamin D3 after surgery. Patients without risk (parathyroid hormone, PTH > 15 pg/ml) were not treated. Patients with a low risk (PTH ≥ 6 ≤ 15 pg/ml and Ca > 2.0 mmol/l) received 3 g calcium, patients with a high risk (PTH ≥ 6 ≤ 15 pg/ml and Ca < 2.0 mmol/l) received 3 g calcium and 2 × 0.5 µg vitamin D3 and patients with a very high risk (PTH < 6 pg/ml) got 4 g calcium and 2 × 0.5 µg vitamin D3.

RESULTS

In this study 415 patients were included (230 prospectively and 185 retrospectively). Serum calcium of patients with individual substitution increased significantly at day 1 (p = 0.0001) and the number of patients with critical hypocalcemia (Ca < 2.0 mmol/l) decreased by half (27% vs. 12.2%; p = 0.0001). There was a significantly lower rate of symptomatic patients (24.9% vs 13.0%; p = 0.002) and a clear reduction of patients with a prolonged hospitalization (10.8% vs. 6.5%; p = 0.08). The rate of permanent hypocalcemia was comparable (2.2% vs. 2.1%). In the risk groups there was a significantly different rate of hypocalcemia: patients without risk (n = 170) in 2.2%, patients with low risk (n = 36) in 25%, patients with high risk (n = 13) in 69.2% and patients with very high risk (n = 11) in 71%.

CONCLUSION

This new treatment regimen is practicable, significantly lowers the symptoms, also in comparison to the literature and shows a clear differentiation between the risk groups.

Effect of autotransplantation of a parathyroid gland on hypoparathyroidism after total thyroidectomy

BACKGROUND

The effect of parathyroid autotransplantation on hypoparathyroidism is not fully understood. The purpose of the study was to determine the effect of autotransplantation of a parathyroid gland on the incidence of hypoparathyroidism and recovery of parathyroid function at 6 months after total thyroidectomy with central neck dissection for papillary thyroid carcinoma.

METHODS

All patients with autotransplantation of a parathyroid gland (no inadvertent parathyroidectomy) (group A), in situ preservation of all parathyroid glands (no autotransplantation and inadvertent parathyroidectomy) (group B) or inadvertent removal of a parathyroid gland (no autotransplantation) (group C) who underwent first-time total thyroidectomy with central neck dissection for papillary thyroid carcinoma between January 2013 and June 2016 were included retrospectively.

RESULTS

Of the 702 patients, 383, 297 and 22 were respectively included in the groups A, B and C. The overall rates of transient and permanent hypoparathyroidism were 37.6% and 1.0%. The incidence of transient hypoparathyroidism was 43.9, 29.0 and 45.5% (A vs B, P = 0.000; A vs C, P = 1.000), and the incidence of permanent hypoparathyroidism was 1.0, 0.7 and 4.5% (P > 0.05). The recovery rates of serum parathyroid hormone levels were 71.4, 72.2 and 66.0% at 6-month follow-up (P > 0.05).

CONCLUSION

Autotransplantation of a parathyroid gland does not affect the incidence of permanent hypoparathyroidism, but increases the risk of transient hypoparathyroidism when the rest of parathyroid glands are preserved in situ. At least 2 parathyroid glands should be preserved during total thyroidectomy with central neck dissection to prevent permanent hypoparathyroidism.

To identify or not to identify parathyroid glands during total thyroidectomy

Hypoparathyroidism is one of the most common complications after total thyroidectomy and may impose a significant burden to both the patient and clinician. The extent of thyroid resection, surgical techniques, concomitant central neck dissection, parathyroid gland (PG) autotransplantation and inadvertent parathyroidectomy have long been some of the risk factors for postoperative hypoparathyroidism. Although routine identification of PGs has traditionally been advocated by surgeons, recent evidence has suggested that perhaps identifying fewer number of in situ PGs during surgery (i.e., selective identification) may further lower the risk of hypoparathyroidism. One explanation is that visual identification may often lead to subtle damages to the nearby blood supply of the in situ PGs and that may increase the risk of hypoparathyroidism. However, it is worth highlighting the current literature supporting either approach (i.e., routine vs. selective) remains scarce and because of the significant differences in study design, inclusions, definitions and management protocol between studies, a pooled analysis on this important but controversial topic remains an impossible task. Furthermore, it is worth nothing that identification of PGs does not equal safe preservation, as some studies demonstrated that it is not the number of PGs identified, but the number of PG preserved in situ that matters. Therefore a non-invasive, objective and reliable way to localize PGs and assess their viability intra-operatively is warranted. In this aspect, modern technology such as the indocyanine green (ICG) as near-infrared fluorescent dye for real-time in situ PG perfusion monitoring may have a potential role in the future.

Short and long-term impact of parathyroid autotransplantation on parathyroid function after total thyroidectomy

The most common complication of total thyroidectomy is parathyroid insufficiency. Acute, transient, post-operative hypoparathyroidism increases length of hospitalization, morbidity and cost associated with total thyroidectomy. While permanent hypoparathyroidism poses a significant medical burden with lifetime medication, regular follow up and considerable disease burden related to chronic renal failure and other sequelae. Parathyroid autotransplantation has been demonstrated to result in biochemically functional grafts, leading to the procedures' common use during total thyroidectomy. The clearest indications for parathyroid auto transplantation are inadvertently removed or devascularized parathyroid glands. Some centers utilize routine autotransplantation to reduce the risk of permanent hypoparathyroidism. Novel fluorescence techniques to aid in parathyroid detection during thyroid surgery are under evaluation. This review aims to define the role and impact of parathyroid autotransplantation undertaken during total thyroidectomy.