Risk factors for hypocalcemia and hypoparathyroidism following thyroidectomy: a retrospective Chinese population study

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.

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.

Frequency and Risk Factors of Permanent Hypoparathyroidism After Total Thyroidectomy: An Experience at a Tertiary Care Hospital in Pakistan

OBJECTIVES

Thyroid surgeries are among the most common operations performed in the world. Hypocalcemia following total thyroidectomy (TT) is a common complication that is sometimes difficult to correct. This study aims to determine the frequency of hypocalcemia and permanent hypoparathyroidism (PtHPT) following TT.

METHODS

A total of 363 patient records were reviewed who underwent TT for any reason. Thirty-eight patients did not have a follow-up in the clinic in the postoperative period and were excluded from the final analysis with the final sample as 325. For patients who developed hypocalcemia during the postoperative hospital stay, their lowest calcium levels were recorded and medical records were reviewed for the period of one year for the requirement of oral calcium and active form of vitamin D (calcitriol or alpha calcidiol) in the outpatient setting. Patients who required calcium and vitamin D supplementation for up to 1 year were labeled as having PtHPT. Risk factors were analyzed among those who developed PtHPT.

RESULTS

From a total of 325 patients postoperative hypocalcemia developed in 163 (50.2%) patients, and 162 (49.8%) patients remained normocalcemic. Permanent hypoparathyroidism was found in 42(12.9%) patients and transient HPT in 121 (37.2%). Age, severe postoperative hypocalcemia (PoHC), and readmission for hypocalcemia were independent risk factors for PtHPT.

CONCLUSIONS

Transient hypoparathyroidism (THPT) is common in our setup. Patients who develop severe hypocalcemia postoperatively and need readmission should be closely followed for the development of PtHPT.

Neck Sinus Post-Thyroidectomy Secondary to Retained Oxidized Regenerated Cellulose: A Case Report

The present study aims to report the first case of chronic neck sinus post-thyroidectomy caused by oxidized regenerated cellulose (ORC). A 55-year-old female patient underwent a total thyroidectomy operation. Three months after the surgery, the patient presented with persistent purulent discharge and sinus at the site of the drain. A CT scan of the neck showed a fistula tract, deep-neck fluid collection, and bilateral paratracheal high-density lesions at the thyroid bed, suggesting infected foreign bodies. The patient underwent surgery, during which the mesh of the ORC was found nonresorbed at the paratracheal space. The treatment involved neck exploration with the removal of all retained material and excision of the sinus tract. The patient had a favorable outcome following the surgical excision of the sinus tract and the removal of retained hemostatic materials. Further research is needed to explore the risk factors and preventive measures for neck sinus formation to enhance the safety and outcomes of thyroidectomy.

Risk Factors for Hypoparathyroidism after Thyroid Surgery: A Single-Center Study

BACKGROUND

Hypoparathyroidism is one of the most common complications after thyroidectomy. This study evaluated the incidence and potential risk factors for postoperative hypoparathyroidism after thyroid surgical procedures in a single high-volume center.

METHODS

In this retrospective study, in all patients undergoing thyroid surgery from 2018 to 2021, a 6 h postoperative parathyroid hormone level (PTH) was evaluated. Patients were divided into two groups based on 6 h postoperative PTH levels (≤12 and >12 pg/mL).

RESULTS

A total of 734 patients were enrolled in this study. Most patients (702, 95.6%) underwent a total thyroidectomy, while 32 patients underwent a lobectomy (4.4%). A total of 230 patients (31.3%) had a postoperative PTH level of <12 pg/mL. Postoperative temporary hypoparathyroidism was more frequently associated with female sex, age < 40 y, neck dissection, the yield of lymph node dissection, and incidental parathyroidectomy. Incidental parathyroidectomy was reported in 122 patients (16.6%) and was correlated with thyroid cancer and neck dissection.

CONCLUSIONS

Young patients undergoing neck dissection and with incidental parathyroidectomy have the highest risk of postoperative hypoparathyroidism after thyroid surgery. However, incidental parathyroidectomy did not necessarily correlate with postoperative hypocalcemia, suggesting that the pathogenesis of this complication is multifactorial and may include an impaired blood supply to parathyroid glands during thyroid surgery.

Intraoperative quantitative assessment of parathyroid blood flow during total thyroidectomy using indocyanine green fluorescence imaging ‐ surgical strategies for preserving the function of parathyroid glands

Objective

We investigated the factors affecting postoperative parathyroid gland (PTG) function and devised an objective index to predict the postoperative PTG function during total thyroidectomy.

Method

This was a retrospective clinical review of 21 consecutive patients who were diagnosed with papillary thyroid carcinoma and underwent total thyroidectomy. The maximum intensity ratio (MIR) was determined as the maximum fluorescence intensity after ICG injection divided by the intensity before ICG injection.

Results

Postoperative hypoparathyroidism is significantly associated with simultaneous central neck dissection (CND) and lateral neck dissection (LND) (p = .032). The Spearman correlation test showed a moderate correlation between the MIR and iPTH levels (p = .0047). The optimal MIR cutoff value for predicting postoperative hypoparathyroidism was 2.14 with area under the curve = 0.904 (sensitivity: 0.769 and specificity: 1.00).

Conclusion

CND + LND was significantly associated with postoperative hypoparathyroidism. MIR was found useful in predicting the postoperative PTG function.

Level of Evidence: 3b.

Trastornos posoperatorios del metabolismo del calcio postiroidectomía

Introducción: revisión narrativa que revela como la tiroidectomía ha aumentado en los últimos años y con ella sus complicaciones: la hipocalcemia y el hipoparatiroidismo. Métodos: los motores de búsqueda utilizados fueron PubMed, Clinical Key, Embase, Cochrane y Lilacs, se incluyeron referencias en español e inglés, publicadas entre 2016 y 2020. Los artículos seleccionados se revisaron utilizando CONSORT, STROBE o PRISMA, según el caso. Resultados: fueron seleccionados 35 artículos que tenían relación directa con el tema, entre ellos: metanálisis, revisiones sistemáticas, estudios prospectivos y observacionales, revisiones narrativas y consensos de expertos, procedentes de los cinco continentes. La hipocalcemia y el hipotiroidismo en sus dos formas se relacionan con la afectación de la vascularización de las glándulas paratiroides o su exérecis accidental, existiendo factores predisponentes propios del paciente, derivados de la técnica quirúrgica o la característica patológica de la lesión en el tiroides. Como estrategias de prevención disponemos de herramientas ópticas para definir en el perioperatorio la disposición de las paratiroides; además existe la posibilidad de autotrasplantarlas al identificarlas en la pieza anatómica. El mejor marcador del estado metabólico del calcio es la PTHi. Conclusiones: la preservación de las paratiroides y de su irrigación es la mejor estrategia para prevenir los trastornos posoperatorios del calcio.

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.

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.

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.

Hypocalcemia prevention and management after thyroidectomy in children: A systematic review

INTRODUCTION

Hypocalcemia is the most common complication following thyroidectomy in children. Guidelines to manage post-thyroidectomy hypocalcemia are available for adults, but not children. The objective of this review was to identify practices related to hypocalcemia prevention and management in pediatric patients.

METHODS

We identified studies examining the prevention and management of hypocalcemia in pediatric patients post-thyroidectomy within PubMed, EMBASE, Web of Science and Cochrane databases. Three independent reviewers screened citations and reviewed full-text papers.

RESULTS

A total of 15 studies were included, representing 1552 patients. The overall study quality was weak with lack of randomization and inconsistent outcome reporting. The pooled incidence of hypocalcemia from the 15 studies was 35.5% for transient hypocalcemia and 4.2% for permanent hypocalcemia. All studies discussed post-operative hypocalcemia treatment, with most patients requiring admission for intra-venous calcium therapy. One study described a protocol discharging asymptomatic patients on calcitriol and calcium. Three studies discussed preoperative calcium supplementation in patients at risk of hypocalcemia. No studies examined routine use of calcium and/or vitamin D supplementation to prevent post-operative hypocalcemia.

CONCLUSION

A significant number of children undergoing thyroidectomy develop hypocalcemia. Despite this high incidence, our systematic review demonstrates significant practice variation surrounding post-thyroidectomy hypocalcemia prevention and management in children.

LEVEL OF EVIDENCE

III (systematic review of studies of which some were case-control studies (III) and some were case series (IV)).

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.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Pediatric differentiated thyroid carcinoma: An update from the APSA Cancer Committee

BACKGROUND

Differentiated thyroid carcinomas (DTCs) are rare in young children but represent almost 10% of all malignancies diagnosed in older adolescents.

METHODS

This article reviews the recent literature describing surgical therapeutic approaches to pediatric DTC, associated complications, and long-term recurrence and survival outcomes.

RESULTS

Similar to adult thyroid cancers, pediatric DTCs are more common in females and are associated with thyroid nodules, family history of thyroid cancer, radiation exposure, iodine deficiency, autoimmune thyroid disease, and genetic syndromes. Management of thyroid cancers in children involves ultrasound imaging, fine needle aspiration, and surgical resection with treatment decisions based on clinical and radiological features, cytology and risk assessment.

CONCLUSIONS

Total thyroidectomy and compartment based resection of clinically involved lymph node basins form the cornerstone of treatment of DTC. There is an evolving literature regarding the use of molecular genetics to inform treatment strategies and the use of targeted therapies to treat iodine refractory and surgically unresectable progressive disease.

TYPE OF STUDY

Summary review.

LEVEL OF EVIDENCE

This is a review article of previously published Level 1-5 articles that includes expert opinion (Level 5).

Age, Gender and Season Are Good Predictors of Vitamin D Status Independent of Body Mass Index in Office Workers in a Subtropical Region

This study aimed at determining the prevalence and predictors of hypovitaminosis D (serum 25-hydroxyvitamin D < 30 ng/mL) among office workers in a subtropical region from an electronic hospital database. Totally, 2880 office workers aged 26–65 years who received health examinations with vitamin D status and total calcium concentrations at a tertiary referral center were retrospectively reviewed. Subjects were divided into groups according to genders, age (i.e., 26–35, 36–45, 46–55, 56–65), body-mass index (BMI) (i.e., obese BMI ≥ 30, overweight 25 ≤ BMI < 30, normal 20 ≤ BMI < 25, and underweight BMI < 20) and seasons (spring/winter vs. summer/autumn) for identifying the predictors of hypovitaminosis D. Corrected total calcium level <8.4 mg/dL is considered as hypocalcemia. Multivariate logistic regression demonstrated that females (AOR 2.33, (95% CI: 1.75, 3.09)), younger age (4.32 (2.98, 6.24), 2.82 (1.93, 4.12), 1.50 (1.03, 2.17)), and season (winter/spring) (1.55 (1.08, 2.22)) were predictors of hypovitaminosis D, whereas BMI was not in this study. Despite higher incidence of hypocalcemia in office workers with hypovitaminosis D (p < 0.001), there was no association between vitamin D status and corrected total calcium levels. A high prevalence (61.9%) of hypovitaminosis D among office workers in a subtropical region was found, highlighting the importance of this occupational health issue.

The predictive factors for postoperative hypoparathyroidism and its severity on the first postoperative day after papillary thyroid carcinoma surgery

PURPOSE

The purpose of the study was to investigate the predictive factors for hypoparathyroidism and its severity on the first postoperative day (POD1) after total thyroidectomy (TT) with or without central neck dissection (CND) in patients with papillary thyroid carcinoma (PTC).

METHODS

From February 2014 to February 2019, 2550 PTC patients were admitted to our department. PTC patients who underwent TT were enrolled in this study. A parathyroid hormone (PTH) level lower than 15 pg/mL on POD1 was defined as hypoparathyroidism, and the severity of hypoparathyroidism was classified into three categories according to the level of PTH on POD1: mild hypoparathyroidism (10 pg/mL ≤ PTH < 15 pg/mL), moderate hypoparathyroidism (5 g/mL ≤ PTH < 10 pg/mL), and severe hypoparathyroidism (PTH < 5 pg/mL). Multiple clinical, pathological and surgical parameters of these two different groups were compared and analyzed to demonstrate the possible causes of hypoparathyroidism. Furthermore, patients who developed postoperative hypoparathyroidism were also included in a subgroup analysis according to the severity of their hypoparathyroidism. The underlying factors affecting different severities of hypoparathyroidism were also illustrated with univariate and multivariate analyses.

RESULTS

Ultimately, 690 patients who underwent TT were enrolled in this retrospective study. Through the univariate analysis, different surgeons (P < 0.001), extent of CND (P = 0.009), prophylactic calcium supplementation (PCS) (P < 0.001), preoperative (pre-op) PTH level (P < 0.001), and pre-op phosphorus concentration (P = 0.022) were found to be significantly correlated with postoperative hypoparathyroidism. According to the multivariate analysis, PCS was the only independent high-risk factor for hypoparathyroidism. In the univariate analysis of patient subgroups with different severities of hypoparathyroidism, we demonstrated that the tumor T stage (P = 0.021) and pre-op PTH level (P < 0.001) were associated with the severity of hypoparathyroidism. Furthermore, after the multivariate analysis, hypertension (P < 0.001) and pre-op PTH (P < 0.001) were the two independent predictive factors for the severity of hypoparathyroidism after surgery.

CONCLUSIONS

Postoperative PCS could increase the risk for PTC patients developing hypoparathyroidism after thyroid surgery. Patients with a history of hypertension and a relatively high pre-op PTH level may not develop severe hypoparathyroidism after TT with CND.

A simple, efficient, and safe way of finding recurrent laryngeal nerve beneficial for PTC patients

BACKGROUND

More surgeons have known the importance of parathyroid grand and recurrent laryngeal nerve protection in the surgery, but there is still plenty of scope to improve the surgical techniques. This study aims at investigating whether the improved method of finding recurrent laryngeal nerve (RLN) can protect parathyroid grand and RLN.

METHODS

One hundred fifty-eight patients were enrolled and divided randomly into the test and control group according to different methods of finding RLN in the surgery. In the experimental group the author could quickly find the laryngeal recurrent nerve in the lower part of the neck and separate along the surface of the recurrent laryngeal nerve to the point where the recurrent laryngeal nerve gets into the larynx close to the thyroid gland named lateral approach, while in the control group the author severed the middle and lower thyroid vein and raised the lower thyroid pole to look for the RLN near the trachea by the blunt separation.

RESULTS

The author identified 152 and 159 parathyroid glands in the test and control group, respectively and there were a lower ratio of auto-transplantation and less operative time in the test group compared with that in the control group. The author also found that the parathyroid hormone level (1 day and 2 months) in the test group was higher than that in the control group. There were no differences in metastatic LN and recurrent laryngeal nerve palsy in the 2 groups.

CONCLUSION

The improved method of finding RLN is a simple, efficient and safe way, and easy to implement.

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.

Magnesemia: an independent risk factor of hypocalcemia after thyroidectomy

Background

This study was designed to investigate the impact of serum magnesium (Mg) levels on hypocalcemia after thyroidectomy.

Patients and methods

In total, 242 patients with differentiated thyroid cancer were retrospectively analyzed.

Results

Multivariate regression analysis showed hypomagnesemia was an independent risk factor for hypocalcemia (P<0.001). While Mg in low levels (0.66 mmol/L ≤ Po-Mg ≤0.74 mmol/L) increased the risk of hypocalcemia, postoperative serum Ca (Po-Ca) levels were significantly lower in patients with hypomagnesemia than in patients with normomagnesemia (P=0.01), and the former patients suffered significant decreases in serum Ca (P=0.02). Compared to patients with a mild decline of serum Mg after surgery (ΔMg <0.17), serum Ca decline significantly increased (P<0.001) in patients with a severe decline of serum Mg (ΔMg ≥0.17), while the change in amounts of parathyroid hormone (PTH) after surgery was similar between the two groups (P>0.05). In patients with normal Po-Ca levels, hypomagnesemia increased the risk of symptoms related to hypocalcemia by 4.478 times (OR =5.478, 95% CI 1.724–17.403).

Conclusion

Hypomagnesemia, or even a low serum Mg level within the normal range, can increase the risk of hypocalcemia. After excluding the potential effects of PTH on serum magnesium and calcium, serum Mg reduction is one of the most important factors that influences postoperative serum Ca reduction. What’s more, hypomagnesemia is closely linked with symptoms.

Hypocalcemia after Total Thyroidectomy in Graves Disease

CONTEXT

Total thyroidectomy has been shown to provide a cost-effective and efficient method of permanently treating Graves disease; however, hypocalcemia can be a common complication.

OBJECTIVE

To evaluate the risk of hypocalcemia after total thyroidectomy in patients with vs without Graves disease.

DESIGN

The 2016 American College of Surgeons National Surgical Quality Improvement Program participant use data files for procedure-targeted thyroidectomy and from 5871 patients were merged. This study included any patient who underwent total thyroidectomy.

MAIN OUTCOME MEASURES

Whether symptomatic hypocalcemia developed anytime within 30 days after the thyroidectomy. A clinically severe hypocalcemic event was also evaluated as a secondary outcome measure.

RESULTS

Of the 2143 patients who underwent total thyroidectomy, 222 patients experienced hypocalcemia after surgery, 124 of whom had symptomatic hypocalcemia postoperatively. Among patients with hypocalcemia, 16.3% had Graves disease, whereas only 9.4% of patients without Graves disease experienced significant hypocalcemia. Multivariable logistic regression analysis revealed that women (odds ratio = 1.79; 95% confidence interval = 1.16-2.76; p = 0.009) and patients who underwent parathyroid autotransplantation (odds ratio = 1.91; 95% confidence interval = 1.30-2.81; p = 0.001) were at greater risk of development of hypocalcemia. Older patients were less likely to experience hypocalcemia postoperatively (odds ratio = 0.586; 95% confidence interval = 0.44-0.79; p = 0.0001).

CONCLUSION

Patients with Graves disease are about twice as likely to experience hypocalcemia or clinically severe hypocalcemia postoperatively than are patients without the disease.

Frequency of Hypocalcaemia following Total Thyroidectomy

Background & Objective

Patients who undergo Total thyroidectomy are at higher risk for postoperative hypocalcaemia, which can lead to significant short and long term morbidity. The aim of this study was to determine the frequency of postoperative hypocalcaemia undergoing Total thyroidectomy.

Methods

A total of 854 patients who underwent Total thyroidectomy and completion thyroidectomy between January 2003 to December 2016 at Endocrine Surgical unit, Jinnah Postgraduate Medical Centre, Karachi, were included in this retrospective study. Data were obtained for demographics, preoperative diagnosis, postoperative calcium levels, extent of surgery and final surgical pathology.

Results

A total of 854 patients underwent Total thyroidectomy. Of these 87.58% (n=748) were malignant and 12.41% (n=106) were benign. Among the malignant and benign patients, 47.3% (n=404) underwent Total thyroidectomy and 52.69% (n=450) underwent completion thyroidectomy. Overall incidence of transient hypocalcaemia was 7% (n=60) and that of permanent hypocalcaemia was 0.11% (n= 1).

Conclusion

Hypocalcaemia is one of major concern following total- thyroidectomy. Meticulous surgical techniques, identification and preservation of vascularity of parathyroid glands are essential in preventing postoperative hypocalcaemia following total thyroidectomy.

Lymph node ratio predicts recurrence in pediatric papillary thyroid cancer

BACKGROUND

Regional lymph node (LN) metastasis at the time of presentation plays a significant role in predicting recurrence in patients with papillary thyroid cancer (PTC). Multiple studies in the adult population have demonstrated that the lymph node ratio (LNR) in both the central and lateral neck can improve the accuracy of recurrence prediction, but this ratio has not been studied in the pediatric population. In this study, we sought to investigate the LNR in the central and lateral compartments as a prognostic predictor for recurrence in pediatric patients with PTC.

METHODS

A retrospective analysis of pediatric patients (≤21 years old) at a single institution between 2002 and 2014 who underwent total thyroidectomy with prophylactic central neck dissection (TTpCND) with at least 3 sampled nodes or total thyroidectomy with unilateral modified radical neck dissection (TTMRND) with at least 10 sampled nodes, and on whom at least 24 months of follow up data were available was performed. The LNR was defined as the ratio of metastatic LNs to total number of investigated LNs. Recurrence after TTpCND and TTMRND was examined separately as a function of LNR, using the value of 0.45 as a cutoff.

RESULTS

Forty-eight patients met inclusion criteria. Thirty-two underwent TTpCND, and sixteen underwent TTMRND. Median age at time of operation was 17 years (range 6-20), and median duration of follow-up was 53.5 months (range 24-183). In the TTpCND, LNR ranged from 0 to 1.0. There were two recurrences among the eight patients (25%) undergoing TTpCND in patients with LNRs >0.45 and a single recurrence among the 24 patients (4.2%) undergoing TTpCND with an LNR ≤0.45. In the TTMRND, LNR ranged from 0.1 to 1.0. There were 3 recurrences in 12 patients with LNR ≤0.45 (30.8%%) and 4 recurrences in 4 patients with LNR >0.45 (100%) (p = 0.03).

CONCLUSIONS

Although limited by small sample size, LNR may be a useful predictor to stratify the likelihood of recurrence in pediatric patients undergoing TTpCND or TTMRND for pathologic N1a or N1b PTC.

TYPE OF STUDY

Prognosis study / retrospective case series.

LEVEL OF EVIDENCE

Level IV.

Preoperative injection of carbon nanoparticles is beneficial to the patients with thyroid papillary carcinoma: From a prospective study of 102 cases

BACKGROUND

More surgeons had noticed the importance of carbon nanoparticles (CNs) in protection of parathyroid grand in the surgery of thyroidectomy and central lymph lode dissection, but paid less attention to the injection time. The purpose of this study was to investigate whether preoperative injection of CNs can improve the dissection of lymph nodes (LNs) and protect parathyroid grand (PG) for the patients with papillary thyroid carcinoma (TC).

METHODS

A total of 102 consecutive patients were enrolled into this study from August 2016 to June 2017. All the patients were divided randomly into preoperative group and intraoperative group by the injecting time of the CNs. We compared the patients who had CNs injected into thyroid gland 1 month before surgery with a control group of patients who had CNs injected during the operation. The primary endpoints were operative time, numbers of total LN and metastatic LN, ratio of PG auto-transplantation, parathyroid hormone (PTH) level, and postoperative complications.

RESULTS

We identify 206 PGs and 162 PGs in the preoperative and intraoperative group, respectively, (P = .000) and there was low ratio of auto-transplantation in the preoperative group compared with the intraoperative group (39.3% vs 50.62%, P = .003). We also found that the PTH level in the preoperative group was higher than that of preoperative group (2.60 ± 1.00 vs 2.19 ± 0.72, P = .021), and the operation time in the preoperative group was less than the intraoperative group (60.17 ± 6.28 vs 80.94 ± 7.12, P = .000). Meanwhile pathological results revealed 3 PGs of accidental removal occurred in the preoperative group, whereas 9 PGs of accidental removal occurred in the intraoperative group (P = .039). Also there was no difference in the numbers of total and metastatic LN in the 2 groups (P > .05).

CONCLUSION

Preoperative injection of CNs was safe, and can help protect PG and reduce the difficulty of operation.