Early predictors of hypocalcemia after total thyroidectomy: an analysis of 304 patients using a short-stay monitoring protocol

Artificial neural network to predict post-operative hypocalcemia following total thyroidectomy

The primary objective of this study was to use artificial neural network (ANN) to predict the post operative hypocalcemia and severity of hypocalcemia following total thyroidectomy. The secondary objective was to determine the weightage for the factors predicting the hypocalcemia with the ANN. A single center, retrospective case series included treatment-naive patients undergoing total thyroidectomy for benign or malignant thyroid nodules from January 2020 to December 2022. Artificial neural network (ANN) - Multilayer Perceptron (MLP) used to predict post-operative hypocalcemia in ANN. Multivariate analysis was used construct validity. The data of 196 total thyroidectomy cases was used for training and testing. The mean incorrect prediction during training and testing was 3.18% (± σ = 0.65%) and 3.66% (± σ = 1.88%) for hypocalcemia. The cumulative Root-Mean-Square-Error (RMSE) for MLP model was 0.29 (± σ = 0.02) and 0.32 (± σ = 0.04) for training and testing, respectively. Area under ROC was 0.98 for predicting hypocalcemia 0.942 for predicting the severity of hypocalcemia. Multivariate analysis showed lower levels of post operative parathormone levels to be predictor of hypocalcemia (p < 0.01). The maximum weightage given to iPTH (100%) > Need for sternotomy (28.55%). Our MLP NN model predicted the post-operative hypocalcemia in 96.8% of training samples and 96.3% of testing samples, and severity in 92.8% of testing sample in 10 generations. however, it must be used with caution and always in conjunction with the expertise of the surgical team. Level of Evidence - 3b.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-024-04608-9.

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.

Assessing Postoperative Phosphate and Calcium/Phosphate Ratio as Surrogates for Parathyroid Hormone Following Total Thyroidectomy

OBJECTIVE

Evaluate utility of postoperative phosphate and calcium/phosphate ratio (Ca/P) as surrogates for parathyroid hormone (PTH) following total thyroidectomy.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary care hospital.

METHODS

We retrospectively reviewed patients 18 years or older who underwent total thyroidectomy in a tertiary care hospital by a single surgeon from 2015 through 2021. Patients with incomplete data, pre-existing hypoparathyroidism, vitamin D deficiency, or renal failure were excluded. All patients had PTH drawn within 4 hours of surgery and serum calcium, albumin, and phosphate levels on postoperative Day 1. Corrected calcium was used to calculate a Ca/P. Receiver operating characteristic (ROC) curves were generated to compare phosphate level or Ca/P with PTH. Each possible surrogate was assessed relative to PTH cutoffs of less than 5, 10, 15, and 20 pg/mL. A good screening test was defined as having an area under the curve (AUC) greater than 0.8.

RESULTS

A total of 185 patients underwent total thyroidectomy with 1 fellowship-trained otolaryngologist. Most patients were female (62%), median age 48 years. Most surgeries were performed for cancer (68%). Six (3.2%) patients required IV calcium supplementation and 2 (1.1%) required readmission for symptomatic hypocalcemia. ROC curves comparing phosphate and Ca/P to PTH at the listed cutoffs demonstrated AUC ranging from 0.55 to 0.66 and 0.61 to 0.79, respectively. None met the threshold for a good screening test.

CONCLUSION

Postoperative phosphate and Ca/P ratio are not surrogates for PTH levels following total thyroidectomy. More research is needed to identify cost-effective strategies for postoperative calcium monitoring in patients undergoing total thyroidectomy.

LEVEL OF EVIDENCE

Retrospective cohort study.

A Study of Incidence and Management of Postoperative Hypocalcemia in Patients Undergoing Near-Total and Total Thyroidectomy

To study the incidence and management of postoperative hypocalcemia in participants undergoing near-total (NTT) and total thyroidectomy (TT) at a tertiary health care center. This is an observational prospective study. Patients posted for NTT and TT in our institute and meeting the inclusion criteria were included. A total of 45 participants were enrolled. The serum calcium was measured on postoperative day 2, at the time of discharge and on 3 months follow-up. A combination of injectable and oral calcium supplements with or without vitamin D sachet was used for the treatment of hypocalcemia. Hypocalcemia was observed in 49% cases. Women were observed to develop hypocalcemia at a higher rate than men. Incidence of hypocalcemia was more in TT patients than NTT patients. Cases with malignant pathology were more susceptible to develop hypocalcemia than those with benign pathology. Operated TT with concomitant neck dissection were at higher risk for development of hypocalcemia. There was no significant association between age and incidence of hypocalcemia. Serum calcium measured on postoperative day 2 was a reliable indicator of risk of hypocalcemia. The early measurement of serum calcium level is a reliable indicator of the risk of hypocalcemia. Standardized treatment of hypocalcemic patients with calcium and vitamin D supplements can reduce the incidence and morbidity associated with postoperative hypocalcemia.

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.

Development of a tool to calculate the probability of hypocalcemia after total thyroidectomy: a prospective study

PURPOSE

This study aimed to evaluate the ability of the percentage of decrease in serum PTH level in the first 8 h after total thyroidectomy (TT) to predict hypocalcemia requiring Ca supplementation and develop a tool to predict it.

METHODS

97 patients who underwent TT with measurement of preoperative parathyroid hormone (PTH) levels were prospectively evaluated 1 and 8 h after TT; postoperative magnesium (Mg2PO) and phosphorus levels were evaluated on the 2nd day after surgery. The percentage of decrease in PTH level 1 h (%dPTH1h) and 8 h (%dPTH8h) postoperatively and predictors of hypocalcemia requiring Ca supplementation were evaluated and an equation was developed to predict this outcome.

RESULTS

%dPTH1h (p = 0.002), %dPTH8h (p = 0.001) and (Mg2PO) (p < 0.01) were isolated predictors of postoperative hypocalcemia requiring Ca supplementation. The data obtained led to the development of two tools to predict this complication.

CONCLUSIONS

The percentage of decrease in PTH level 1 h and 8 h postoperatively and the magnesium level on the 2nd day after surgery were predictors of more severe hypocalcemia, and an auxiliary tool for predicting this complication was developed.

Risk factors for postoperative hypocalcemia following total thyroidectomy: a retrospective study

BACKGROUND

and Objectives: Hypocalcemia is a commonly reported complication after thyroid surgery. Many possible risk factors have been identified. The purpose of this study is to analyze various risk factors possibly associated with development of postoperative hypocalcemia after thyroid surgery by dividing the sample population into postoperative hypocalcemia and normal calcium groups.

DESIGN

Retrospective.

SETTING

Multiple centers in the Makkah region of Saudi Arabia.

PATIENTS AND METHODS

Risk factors for postoperative hypocalcemia that were obtained for analysis include patient factors, perioperative blood parameters factors, disease-related factors, and surgical factors. Postoperative hypocalcemia was defined as a reduction of the total calcium level to <8.0 mg/dL. Hypocalcemic and normocalcemic patients were compared by multivariate logistic regression.

MAIN OUTCOME MEASURES

Distinguish independent risk factors for postoperative hypocalcemia after thyroidectomy.

SAMPLE SIZE

215 patients.

RESULTS

The incidence of hypocalcemia was 52.1% (112 of 215 patients). According to multivariate analysis, statistically significant risk factors for predicting postoperative hypocalcemia included postoperative parathyroid hormone level <10 pg/dL, inadvertent parathyroid gland resection, and neck dissection surgeries.

CONCLUSION

The causes of postoperative hypocalcemia are multi-factorial. Because many of these factors are modifiable, they should be identified postoperatively to distinguish high-risk groups and implement early preventive measures.

LIMITATIONS

Retrospective with a relatively small size. We encourage additional prospective studies with a larger sample size in multiple regions of the country, which might reveal further significant results.

Preoperative Vitamin D and Calcium Administration in Patients Undergoing Thyroidectomy: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Objective

This systematic review and meta-analysis aimed to assess whether preoperative administration of calcium and vitamin D prevents postoperative hypocalcemia.

Data Sources

A computerized search in Medline, Embase, and CENTRAL databases was performed.

Review Methods

Trials comparing preoperative calcium and vitamin D administration with either placebo or nothing were eligible for inclusion. The primary outcomes were the occurrence of laboratory hypocalcemia, mean postoperative calcium level, and symptomatic hypocalcemia. The secondary outcomes were the development of permanent hypoparathyroidism and length of hospitalization. Continuous outcomes were represented as standardized mean difference (SMD), and dichotomous outcomes were represented as risk ratio (RR).

Results

Nine trials that enrolled 1079 patients were found eligible. Postoperative laboratory hypocalcemia occurred less in patients who received preoperative calcium and vitamin D, but it was not statistically significant (RR = 0.77, 95% CI: 0.60-1.00; P = .05). Mean postoperative calcium level was significantly higher in the intervention group (SMD = 0.10, 95% CI: 0.07-0.12; P < .00001). The number of patients with symptomatic hypocalcemia was significantly lower in the intervention group (RR = 0.54, 95% CI: 0.38-0.76; P = .0005). There was no significant difference between the 2 groups in cases of permanent hypoparathyroidism and length of hospitalization.

Conclusion

Administration of calcium and vitamin D preoperatively achieves lower rates of postthyroidectomy symptomatic hypocalcemia in comparison with no intervention.

A symptom-based algorithm for calcium management after thyroid surgery: a prospective multicenter study

Objective

Evidence-based treatment guidelines for the management of postthyroidectomy hypocalcemia are absent. The aim of this study was to evaluate a newly developed symptom-based treatment algorithm including a protocolized attempt to phase out supplementation.

Methods

In a prospective multicenter study, patients were treated according to the new algorithm and compared to a historical cohort of patients treated with a biochemically based approach. The primary outcome was the proportion of patients receiving calcium and/or alfacalcidol supplementation. Secondary outcomes were calcium-related complications and predictors for supplementation.

Results

One hundred thirty-four patients were included prospectively, and compared to 392 historical patients. The new algorithm significantly reduced the proportion of patients treated with calcium and/or alfacalcidol during the first postoperative year (odds ratio (OR): 0.36 (95% CI: 0.23-0.54), P < 0.001), and persistently at 12 months follow-up (OR: 0.51 (95% CI: 0.28-0.90), P < 0.05). No severe calcium-related complications occurred, even though calcium-related visits to the emergency department and readmissions increased (OR: 11.5 (95% CI: 4.51-29.3), P <0.001) and (OR: 3.46 (95% CI: 1.58-7.57), P < 0.05), respectively. The proportional change in pre- to postoperative parathyroid hormone (PTH) was an independent predictor for supplementation (OR: 1.04 (95% CI: 1.02-1.07), P < 0.05).

Conclusions

Symptom-based management of postthyroidectomy hypocalcemia and a protocolized attempt to phase out supplementation safely reduced the proportion of patients receiving supplementation, although the number of calcium-related hospital visits increased. For the future, we envision a more individualized treatment approach for patients at risk for delayed symptomatic hypocalcemia, including the proportional change in pre- to post- operative PTH.

Serum Parathyroid Hormone and Vitamin D Levels as Predictors of Hypocalcemia after Total/ Near Total Thyroidectomy

BACKGROUND

Post-operative Hypocalcaemia is the most-common complication of total and near-total thyroidectomy which is a selective treatment for benign and malignant thyroid diseases. Incidence ranges from 0.5-50%.

OBJECTIVES

The role of vitamin-D and Parathyroid hormone(PTH) in incidence of Hypocalcemia after thyroidectomy has been taken into consideration.

METHODS

This is a prospective interventional study is conducted in Kasturba Medical College and hospital, Manipal after taking written informed consent from the participants. It aimed at surveying the serum level of preoperative Vitamin D, PTH and calcium before total-thyroidectomy surgery and its relationship with the incidence of postoperative hypocalcemia after the surgery. The study was done on 70 patients who were-planned for total/near total thyroidectomy. Preoperative Vitamin D, PTH, calcium and Postoperative 4 hours-PTH, Calcium were measured on POD-1, POD-2-4, the results obtained were then analysed.

RESULTS

 Considering the cut-off of calcium as 8.6mg/dl, 42 patients developed hypocalcemia on POD-1, 28 patients on POD-2. Preoperative calcium and postoperative PTH levels in people having hypocalcaemia where significantly less compared to the patients having normal calcium. 4-hours post-operative PTH measurements showed 51% sensitivity, 100% specificity and strong co-relation between postoperative hypocalcemia and drop in PTH levels- (p=<0.001). Out of 42 patients who developed hypocalcemia 28- (65%) patients had vitamin-D deficiency(p=0.5) on POD-1 and out of 51 patients with hypocalcemia on POD 2-4, 33(78%) had-vitamin-D-deficiency(p=0.3852). Which was not statically significant.

CONCLUSION

4 hours post-operative PTH level is a predictor of early postoperative hypocalcemia, by detecting this we can effectively manage postoperative hypocalcemia.

The role of preoperative vitamin D and calcium in preventing post-thyroidectomy hypocalcaemia: a systematic review

BACKGROUND

The thyroid gland plays an important endocrine function regulating metabolism, growth and development. A variety of benign and malignant conditions necessitate surgical removal of the thyroid gland, either in its entirety, or partially. Thyroidectomy is the most commonly undertaken endocrine surgery. Hypocalcaemia, occurring at a rate of approximately 25%, is the most common complication following total thyroidectomy. Hypocalcaemia can increase healthcare costs requiring further investigations, treatment and delaying discharge. Severe hypocalcaemia can be potentially life threatening. It has been demonstrated that routine post-operative supplementation with Vitamin D and calcium, can reduce post-operative hypocalcaemia, at present it is unclear whether preoperative supplementation has a similar effect.

METHODS

This systematic review includes randomised controlled trials on human adult subjects, who received preoperative Vitamin D and/or calcium, and which studied the effect on post-operative hypocalcaemia following total or near total thyroidectomy. There were no restrictions in respect of post-operative supplementation regimen. Studies were limited to those published in English.

RESULT

Seven of the eleven trials demonstrated a reduction in either laboratory or clinical hypocalcaemia with preoperative supplementation. This benefit was most likely to be seen when postoperative supplementation was performed on an as needed basis. IV calcium was required to treat resistant or severe hypocalcaemia, in five of the eleven trials, in each of these five trials, rates of IV replacement were lower in the preoperative supplementation group.

CONCLUSION

The use of preoperative Vitamin D, with or without calcium, may provide a modest reduction in the incidence of laboratory and clinic hypocalcaemia following total or near total thyroidectomy. There is a trend toward a reduced requirement for IV calcium with preoperative supplementation. Larger robust randomised trials are needed to provide a definitive answer. Preoperative supplementation can be considered in patients undergoing total or near total thyroidectomy.

Intact Parathyroid Hormone Levels in Predicting Postoperative Hypocalcaemia After Total Thyroidectomy in South Indian Population: Cross Sectional Study

Hypocalcaemia being one of the most common complications after total thyroidectomy may not be avoidable in all cases. This study evaluated the effectiveness of intact Parathyroid hormone (iPTH) measured at 1-h after total thyroidectomy in predicting postoperative hypocalcaemia in early postoperative period in South Indian population. Patients who underwent total thyroidectomy in our institute from 2016 to 2018 were included. Preoperative calcium and iPTH levels were measured. Patients' iPTH level was measured 1 h after surgery and serum calcium level was measured at 24 h after surgery. Patients were also monitored clinically for any symptoms and signs of hypocalcaemia. A total of 57 patients were studied. The malignant causes accounted for 75.4% with papillary carcinoma thyroid being the most common cause. 65.7% of patients who underwent total thyroidectomy and 100% of patients who underwent total thyroidectomy with neck dissection developed hypocalcaemia. 70% of patients with low iPTH developed hypocalcaemia and none of the patients who had normal iPTH developed hypocalcaemia. This relation was statistically significant with p value of 0.018 (< 0.05). The positive predictive value is 70% and negative predictive value is 100%. Though our study supports the hypothesis that iPTH is effective in predicting hypocalcaemia after total thyroidectomy in the early postoperative period, a larger sample study is needed to further support this. It can be used to consider patients for early discharge or to prophylactically start oral calcium and Vitamin D supplementation based on iPTH levels at 1 h after surgery.

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.

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.

Assessment of Serum Ionized Calcium in the Perioperative Period in Patients Undergoing Total Thyroidectomy

BACKGROUND: The serious complications of total and near-total thyroidectomy vary from hypocalcemia to recurrent laryngeal nerve injury to tension hematoma. Post-operative hypocalcemia is common and has an incidence of 1.3–83% in some studies. AIM: The aim of the study is to evaluate the immediate post-operative sequence of serum-ionized calcium next to entire or close entire thyroidectomy to describe the incidence degree of hypocalcemia. METHOD: One hundred and seventy-four (174) patients who underwent total and near-total thyroidectomy were investigated for serum-ionized calcium level preoperatively and on post-operative day (POD) 1 and 2, searching for difference in serum-ionized calcium level preoperatively. RESULTS: There was a significant difference between pre-operative serum-ionized calcium (Ca++) level and that in POD1. The mean pre-operative ionized Ca was 1.23 ± 0.47 mmol/l, while mean ionized Ca on POD1 was 1.175 ± 0.11 mmol/l proposing decrease in mean of ionized Ca++ in POD1 (p = 0.0001). There was also a significant difference between pre-operative serum-ionized Ca++ level and that in POD2. The mean pre-operative ionized Ca was 1.23 ± 0.47 mmol/l, while the mean of ionized calcium on POD2 was 1.177 ± 0.1 mmol/l suggesting decrease in mean concentration of Ca++ in POD2 (p = 0.0001). CONCLUSION: Significant number of patients who undergo near-total and total thyroidectomy develop decrease in the serum concentration of calcium postoperatively.

Hypocalcemia following total and subtotal thyroidectomy and associated factors

BACKGROUND

Thyroidectomy is one of the common endocrinological surgeries for the treatment of thyroid disorders. Hypocalcemia is the potential complication after thyroidectomy, where is persistency can lead to serious systemic effects. The aim of this study is to evaluate the incidence of hypocalcemia in thyroidectomy patients.

METHODS

In this cross-sectional study, patients referred to (XXX) for thyroidectomy from 2019 to 2020 were enrolled. Preoperative serum calcium and postoperative 24- and 48-h calcium levels were evaluated in these patients. Demographic data (sex and gender), calcium levels, type of thyroidectomy and duration of surgery was recorded for all the patients. SPSS v22 was used for statistical analysis. P < 0.05 was considered as statistically significant.

RESULTS

Of 143 patients included in the study, the mean age was 49.7 ± 10.9 years and 61.5% were females and 38.5% were males. 49% patients had hypocalcemia in the first 24 hours after surgery and 63.6% following 48 hours of the surgery. The difference in calcium levels at three intervals were statistically significant, p = 0.001. The incidence of hypocalcemia was significantly more in women at 48 postoperative hours, p = 0.025. The age and duration of surgery was not significantly correlated with hypocalcemia, p > 0.05, whereas, patients who underwent total thyroidectomy had greater incidence of hypocalcemia 24 hours after the surgery, p = 0.021.

CONCLUSIONS

The incidence of hypocalcemia is greater in total thyroidectomy and female patients. Our study did not report significant correlation between duration of the surgery and age of the patients.

Preoperative vitamin D deficiency is associated with increased risk of postoperative hypocalcemia after total thyroidectomy

Prior single-institution studies suggest that preoperative vitamin D deficiency (VDD) is associated with postoperative hypocalcemia and a prolonged length of hospital stay following total thyroidectomy. In this study, we employ a multi-institutional, de-identified electronic health records database to address this issue. We hypothesize that total thyroidectomy patients with preoperative VDD will be at an increased associated risk of postoperative hypocalcemia and hospitalization. Using Cerner Health Facts, we identified 2447 patients who underwent total or subtotal thyroidectomy between 2008 and 2016 and who had a documented 25-hydroxyvitamin D concentration obtained within 12 months of the surgery date using International Classification of Diseases 9/10, Current Procedural Terminology and Healthcare Common Procedure Coding System codes. Data from 984 patients who underwent total thyroidectomy were analyzed. Analysis of variance models estimated the effect of VDD on postoperative numerical variables. Multiple logistic regression estimated the risk of postoperative hypocalcemia and hospital stay, adjusting for any imbalanced demographic variables and operative characteristics. On average, postoperative total calcium concentrations in the VDD group were lower by 0.3 mg/dL compared with that of the non-VDD group (p<0.01). The risk of postoperative hypocalcemia was 2.2 times higher in the VDD group compared with the non-VDD group (p<0.01). Although the length of hospital stay after thyroidectomy was longer in the VDD group compared with the non-VDD group (p=0.03), VDD is not an independent risk factor for prolonged hospitalization following thyroidectomy (p=0.13). VDD is associated with a higher risk of hypocalcemia following total thyroidectomy. Prethyroidectomy operative screening for VDD should be considered.

Risk factors for postoperative morbidity after thyroid surgery in a PROSPECTIVE cohort of 1500 patients

BACKGROUND

Postoperative hypocalcaemia, recurrent laryngeal nerve palsy and postoperative bleeding are the most frequent postoperative complications after thyroid surgery, and therefore often used as quality indicators of thyroid surgery. We aimed to assess postoperative morbidity in a high-volume endocrine surgery unit, and to detect which factors are associated with higher risks.

METHODS

Prospective surgical cohort in a high-volume tertiary referral centre for endocrine surgery in xxx. The first 1500 patients operated with hemi or total thyroidectomy during 2010-2019 were included. Postoperative hypocalcaemia, recurrent laryngeal nerve palsy and postoperative bleeding were assessed in relation to pre- and peri-operative characteristics using multivariable logistic regression analyses, expressed as odds ratios and 95% confidence intervals.

RESULTS

Overall, 1043 patients (69.5%) received a total thyroidectomy and 457 (30.5%) a hemithyroidectomy. Permanent hypocalcaemia occurred in 3.1%, permanent recurrent laryngeal nerve palsy in 1.8% and surgical reintervention for bleeding in 2.6%. Younger age, female sex and cancer were risk factors for permanent hypocalcaemia. No clear risk factors could be identified for permanent nerve palsy. Female sex, high body mass index and heavier thyroids were protective against postoperative bleeding after total thyroidectomy.

CONCLUSIONS

Surgical experience in endocrine surgery seems beneficial for clinical outcomes and contributes to organizational efficiency. A low complication risk can be obtained by trained high-volume endocrine surgeons, yet the risk is not negligible.

Tiempo óptimo para medición de paratohormona como predictor de hipocalcemia en pacientes posterior a tiroidectomía total

Introducción. La hipocalcemia posterior a tiroidectomía total es una complicación frecuente en la cirugía de tiroides. La hormona paratiroidea ha demostrado ser un predictor confiable para detectar los pacientes con alto riesgo de hipocalcemia significativa y la consecuente necesidad de administrar suplemento de calcio. El objetivo de este estudio fue determinar el tiempo óptimo de medición de la paratohormona para dicho fin. Métodos. Estudio prospectivo realizado en dos instituciones de nivel III en Popayán, Colombia, entre abril de 2016 y febrero de 2018, en el cual se midieron niveles de paratohormona prequirúrgico, a las 0, 2, 4 y 12 horas del postoperatorio, y se compararon con los valores obtenidos a los 3 meses de seguimiento en pacientes sometidos a tiroidectomía total. Se consideró como grupos de riesgo y con necesidad de suplemento de calcio un valor de paratohormona menor de 10 pg/ml o una disminución mayor del 80 % con respecto al valor prequirúrgico. Resultados. Se incluyeron 34 pacientes intervenidos. Tomando como umbral un valor menor de 10 pg/ml, la medición de paratohormona a las 4 horas fue sensible y específica (60 y 93,1 % respectivamente). Para una disminución mayor del 80 % con respecto al valor prequirúrgico, la sensibilidad fue del 60 % y la especificidad del 96,5 %, presentando un valor predictivo positivo de 75 % y negativo del 93,3 %, con una p < 0,001. Discusión. Una disminución mayor del 80 % del valor de paratohormona prequirúrgico medida a las 4 horas después de la tiroidectomía total permite identificar aquellos pacientes con alto riesgo de hipocalcemia significativa, que requieren administración temprana de suplementos de calcio, comparado con la determinación de la disminución a las 0, 2 y 12 horas postoperatorias.

Feasibility of Autofluorescence for Parathyroid Glands During Thyroid Surgery and the Risk of Hypocalcemia: First Results in Belgium and Review of the Literature

Background. Post-operative hypocalcemia remains the most frequent complication after total thyroidectomy. Recently, autofluorescence imaging was introduced to detect parathyroid glands early during dissection. Aim. We aimed to check the feasibility of autofluorescence regarding the number of parathyroid glands visualised and the risk of post-operative hypocalcemia. Methods. In a prospectively gathered cohort of patients undergoing thyroid surgery, we describe the risk of hypocalcemia in relation to the number of parathyroid glands visualised during surgery (and the risk reported in the scientific literature) and the feasibility to obtain an autofluorescence of the parathyroid glands. Results. From 2010 to 2019, 1083 patients were referred for total thyroidectomy in our tertiary referral centre for endocrine surgery, of which, 40 consecutive cases were operated using autofluorescence. Among the autofluorescence group, 14 (35.0%) had all 4 parathyroid glands visualised, compared to 147 (14.1%) in the other patients, without differences in the number of parathyroid glands reimplanted. No permanent hypocalcemia occurred in the autofluorescence group and 17.5% temporary hypoparathyroidism, compared to 3.1% and 31.9% among the other patients, and 4% (95% confidence interval [CI] 3-5%) and 19% (95% CI 15-24%) in the literature. Conclusion. Autofluorescence imaging provides reliable real-time visualisation at any point during thyroid surgery and helps to identify the parathyroid glands before detection with the naked eye. To date, it cannot be used as a standard technique and does not replace meticulous dissection. To become a useful adjunct in peroperative parathyroid management, large multicentre studies need to establish a potential clinical benefit of this novel technique.

A Cohort Study Assessing the Association Between Body Composition Parameters and Symptomatic Hypocalcemia After Total Thyroidectomy

BACKGROUND

Postoperative hypocalcemia is one of the major concerns following thyroidectomy and the most frequent cause of prolonged hospital stay. The aim of this study was to evaluate the relationship between body composition parameters and symptomatic hypocalcemia following total thyroidectomy. In addition, the effects of disease- and patient-related factors on hypocalcemia were investigated.

METHODS

A total of 144 patients were prospectively included between March 2014 and September 2017. Patients were divided into 2 groups according to the presence or absence of clinical symptoms of hypocalcemia. Subsequently, the relationship between body composition parameters and hypocalcemia was evaluated.

RESULTS

Postoperative hypocalcemia-related symptoms occurred in 28 patients (19.4%). Permanent hypocalcemia was not encountered in any patient. Patients with hypocalcemic symptoms were more likely to have nodules ≥40 mm (39.3% vs. 17.2%, P = .011), retrosternal goiters (25.0% vs. 7.8%, P = .017), central lymph node dissection (LND) (32.1% vs. 11.2%, P = .015), and parathyroid autotransplantation (28.6% vs. 3.4%, P < .001) than those without symptoms. However, no differences were observed in the body composition parameters between symptomatic and asymptomatic patients. On multivariate analysis, lower preoperative intact parathyroid hormone (iPTH) levels (odds ratios (ORs) .96, 95% confidence intervals (CIs) .93-.99), the presence of retrosternal goiters (OR 10.26, 95% CI 2.23-47.14), central LND (OR 16.05, 95% CI 3.90-66.07), and parathyroid autotransplantation (OR 36.22, 95% CI 6.76-194.13) predicted hypocalcemia.

DISCUSSION

This study demonstrates that patients with lower preoperative iPTH levels, retrosternal goiters, central LND, and parathyroid autotransplantation are at an increased risk of developing clinical symptoms of hypocalcemia. Body composition parameters have no effect on the incidence of hypocalcemia after total thyroidectomy.

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

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

Predictors of post-thyroidectomy hypocalcaemia: a systematic and narrative review

OBJECTIVE

Hypocalcaemia is the most common complication after total or completion thyroidectomy. This study assesses recent evidence on predictive factors for post-thyroidectomy hypocalcaemia in order to identify the patients affected and aid prevention.

METHOD

Two authors independently assessed articles and extracted data to provide a narrative synthesis. This study was an updated systematic search and narrative review regarding predictors of post-thyroidectomy hypocalcaemia using the Ovid Medline, Embase, Cochrane and Cinahl databases. Results were limited to papers published from January 2012 to August 2019.

RESULTS

Sixty-three observational studies with a total of 210 401 patients met the inclusion criteria. The median incidence was 27.5 per cent for transient biochemical hypocalcaemia, 12.5 per cent for symptomatic hypocalcaemia and 2.2 per cent for permanent hypocalcaemia. The most frequent statistically significant predictor of hypocalcaemia was peri-operative parathyroid hormone level. Symptomatic hypocalcaemia and permanent hypocalcaemia were seen more frequently in patients undergoing concomitant neck dissection.

CONCLUSION

Many factors have been studied for their link to post-thyroidectomy hypocalcaemia, and this study assesses the recent evidence presented in each case.

Preventative and management strategies of hypocalcemia after thyroidectomy among surgeons: An international survey study

OBJECTIVE

To determine international surgeon practice patterns for transient postoperative hypocalcemia in patients undergoing total thyroidectomy.

METHODS

All member surgeons of the American Thyroid Association and the International Association of Thyroid Surgeons were contacted via email to complete a 20-question survey which included both questions about demographic information and preventing and managing postoperative hypocalcemia after thyroidectomy. Univariate analysis was performed to determine whether providers check preoperative vitamin D levels, postoperative calcium trends and/or PTH to assess for postoperative hypocalcemia.

RESULTS

A total of 332 surgeons responded to the survey with 72.26% in practice for >10 years and 82.18% performing >50 total thyroidectomies per year. 13.29% of surgeon's surveyed reported that they routinely check preoperative vitamin D levels. Surgeon case volume, type of practice (academic vs non-academic practice), and geographic location in the US were significant predictors of whether surgeons check preoperative Vitamin D levels. International surgeons were significantly more likely to check both postoperative serum Ca and PTH compared to US based surgeons (p < .01). There was no significance difference in practice patterns based on whether the surgeon was a General Surgeon or an Otolaryngologist.

CONCLUSIONS

Using a questionnaire distributed to both General Surgeons and Otolaryngologists, we demonstrated that there is significant variation in practice patterns between surgeons practicing in the United States and surgeons practicing in other countries, and practice often differs from recommended guidelines.

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.

Vitamin D Status as a Predictor of Postoperative Hypocalcemia after Thyroidectomy

OBJECTIVE

To determine whether perioperative vitamin D levels are predictive of postoperative hypocalcemia in patients receiving thyroidectomy.

STUDY DESIGN

Single center retrospective study.

SUBJECTS AND METHODS

This study included all patients receiving total or completion thyroidectomy between January 2007 and March 2017 at a single tertiary care hospital. 25-Hydroxyvitamin D (25[OH]D) levels were measured within 42 days prior to surgery or 1 day postoperatively. Hypocalcemia was defined as an adjusted serum calcium <8.0 mg/dL (based on albumin levels) or symptomatic hypocalcemia. Univariate analysis was performed with a 2-sample t test and chi-square test, while multivariate analysis was performed with logistic regression analysis to determine whether perioperative 25(OH)D level is a predictor of postoperative hypocalcemia.

RESULTS

A total of 517 subjects were included in the study, 15.7% (n = 81) of whom experienced postoperative hypocalcemia with a mean ± SD serum calcium level of 7.6 ± 0.5 mg/dL as compared with 8.9 ± 0.5 mg/dL in the normocalcemic population (P < .01). The mean 25(OH)D level for patients with hypocalcemia was 24.4 ± 12.0 ng/mL as compared with 27.5 ± 12.2 ng/mL in patients with normocalcemia (P = .038). Subjects who were hypocalcemic experienced a significantly longer hospital stay (2.9 ± 2.5 vs 1.4 ± 1.1 days, P < .01). After adjusting for preoperative calcium, age, and performance of a neck dissection, subjects with a 25(OH)D level <30 ng/mL were significantly associated with postoperative hypocalcemia (odds ratio, 1.9; P = .041; 95% CI, 1.0-3.3).

CONCLUSION

Using a single-center retrospective study design, we demonstrated that 25(OH)D level is a significant predictor of postoperative hypocalcemia after thyroidectomy.

Outcomes of parathyroid gland identification and autotransplantation during total thyroidectomy

PURPOSE

To report the outcomes of parathyroid gland (PG) identification and autotransplantation (autoT) during thyroidectomy.

METHODS

Consecutive total thyroidectomy cases performed by a single surgeon using extracapsular dissection technique were considered. PGs were not intentionally sought during dissection. PG location, number identified and autoT were prospectively recorded and correlated to postoperative outcomes.

RESULTS

In all, 265 cases were included. The mean number of PGs identified per case was 2.7. The number of PGs identified had no correlation to postoperative hypocalcemia. However, independent risk factors for hypocalcemia were female sex, bilateral central compartment neck dissection (CND) and autoT > 1 PG; and for permanent hypoparathyroidism were female sex and bilateral CND. AutoT did not protect against permanent hypoparathyroidism.

CONCLUSION

The number of PGs identified during the course of a standard extracapsular dissection technique had no correlation to postoperative hypocalcemia. Whenever possible, avoiding bilateral CND and careful techniques to preserve PGs in an in situ and viable state, to obviate the necessity for autoT, are recommended.

Post-thyroidectomy emergency room visits and readmissions: Assessment from the Collaborative Endocrine Surgery Quality Improvement Program (CESQIP)

BACKGROUND

This study analyzed independent factors associated with post-thyroidectomy Emergency Room (ER) visits and Hospital Readmissions (HR).

METHODS

This is a retrospective review from the CESQIP registry of 8381 thyroidectomy patients by 173 surgeons at 46 institutions. A total of 7142 ER visits and 7265 HR were analyzed. Multivariable logistic regression analysis was performed to determine the risk factors for an ER visit or HR.

RESULTS

Within 30-days of surgery, rates of all ER visits were 3.4% (n = 250) and all HR were 2.3% (n = 170). Hypocalcemia was the reason for 21.9% of ER encounters and 36.4% of HR. BMI >40 kg/m² was a risk factor for both ER visit (OR1.86) and HR (OR1.94). Surgical duration >3 h (OR2.63), and transection of recurrent laryngeal nerve (OR4.58) were risk factors for HR.

CONCLUSIONS

Strategies to decrease hypocalcemia and improve perioperative care of patients with BMI >40 kg/m² may improve post-thyroidectomy outcome.

Postoperative hypocalcemia: analysis of factors influencing early hypocalcemia development following thyroid surgery

BACKGROUND

Early Hypocalcemia is the most frequent complication after thyroid surgery. Several studies have tried to identify factors (patient caracteristics or surgical technique variations) affecting hypocalcemia following thyroid surgery. This studiy evaluates the role of several factors in postoperative hypocalcemia development.

METHODS

A retrospective study conducted on 2108 patients that underwent thyroid surgery in a single center (1669 women and 439 men). Postoperative early hypocalcemia was defined as serum calcium levels lower than 8,0 mg/dl measured 24 h after surgery. Following factors were evaluated in the study: sex, age, glandular hyperfunction, preoperative diagnosis, preoperative serum calcium levels, preoperative serum PTH levels, type of surgery performed (total thyroidectomy vs. lobectomy); minimally invasive video assisted thyroidectomy (MIVAT); number of parathyroid preserved in situ, postoperative serum calcium levels, changes in perioperative calcium levels (difference between preoperative values ​​and postoperative calcium levels), presence of carcinoma in the surgical specimen, presence of thyroiditis based on histopatology reports.

RESULTS

Among evaluated factors only gender and surgical procedure revealed to be significantly correlated to early hypocalcemia development. In fact female patients experienced postoperative hypocalcemia in 42% (701/1669) of cases, which was signicantly higher than the 21.4% (94/439) identified in men. We also noticed a greater hypocalcemia incidence in patient undergoing total thyroidectomy (38.8%) than in patient undergoing lobectomy group (13.8%). Early hypocalcemia development didn't appear to be related to preoperative serum calcium levels but it showed a statistically significant correlation with perioperative serum calcium level drop.

CONCLUSION

This findings suggest that sex (female gender is a strong risk factor),surgical procedure and perioperative changes in serum calcium are the only factors (among all variables examined) that influence early hypocalcemia development.

Huge variations in definition and reported incidence of postsurgical hypoparathyroidism: a systematic review

PURPOSE

The reported incidence of post surgical hypoparathyroidism (HypoPT) varies greatly. Previous research suggests that the definition of HypoPT is not consistent in the literature. We therefore conducted a systematic review to investigate how HypoPT is defined and whether this definition, as well as the selected threshold for hypocalcemia affects the incidence.

METHODS

Using a predefined search string we identified all articles in PubMed reporting on the incidence of postsurgical HypoPT from 1st January 2010 to January 2017.

RESULTS

We identified 89 articles that employed 20 different definition of HypoPT. The incidence of HypoPT varied from 0.0% to 20.2%. The definitions were not associated with incidence of HypoPT. Use of prophylactic post-operative calcium supplements, however decreased the risk of HypoPT (p = 0.03), and there was a trend towards a lower risk of HypoPT when using a definition of hypocalcemia below lower limit of the reference range (p = 0.09).

CONCLUSION

The large number of definitions of HypoPT, as well as the huge variation in incidence point to a problem suggests that the awareness of HypoPT should be raised. Use of prophylactic post-operative calcium supplements may decrease risk of HypoPT. This, however, may be due to reverse causality as awareness of the risk of HypoPT may promote the use of calcium supplementation.

High-dose preoperative cholecalciferol to prevent post-thyroidectomy hypocalcaemia: A randomized, double-blinded placebo-controlled trial

OBJECTIVE

Post-thyroidectomy hypocalcaemia is a significant cause of morbidity and prolonged hospitalization, usually due to transient parathyroid gland damage, treated with calcium and vitamin D supplementation. We present a randomized, double-blinded placebo-controlled trial of preoperative loading with high-dose cholecalciferol (300 000 IU) to reduce post-thyroidectomy hypocalcaemia.

PATIENTS AND MEASUREMENTS

Patients (n = 160) presenting for thyroidectomy at tertiary hospitals were randomized 1:1 to cholecalciferol (300 000 IU) or placebo 7 days prior to thyroidectomy. Ten patients withdrew prior to surgery. The primary outcome was post-operative hypocalcaemia (corrected calcium <2.1 mmol/L in first 180 days).

RESULTS

The study included 150 patients undergoing thyroidectomy for Graves' disease (31%), malignancy (20%) and goitre (49%). Mean pre-enrolment vitamin D was 72 ± 26 nmol/L. Postoperative hypocalcaemia occurred in 21/72 (29%) assigned to cholecalciferol and 30/78 (38%) participants assigned to placebo (P = 0.23). There were no differences in secondary end-points between groups. In pre-specified stratification, baseline vitamin D status did not predict hypocalcaemia, although most individuals were vitamin D replete at baseline. Post-hoc stratification by day 1 parathyroid hormone (PTH) (<10 pg/mL, low vs ≥10 pg/mL, normal) was explored due to highly divergent rates of hypocalcaemia in these groups. Using a Cox regression model, the hazard ratio for hypocalcaemia in the cholecalciferol group was 0.56 (95%CI 0.32-0.98, P = 0.04) after stratification for Day 1 PTH. Further clinical benefits were observed in these subgroups.

CONCLUSIONS

Pre-thyroidectomy treatment with high-dose cholecalciferol did not reduce the overall rate of hypocalcaemia following thyroidectomy. In subgroups stratified by day 1 PTH status, improved clinical outcomes were noted.

The incidence of post-thyroidectomy hypocalcaemia: a retrospective single-centre audit

INTRODUCTION

The aim of this single centre retrospective observational record-based audit was to assess the incidence of post-thyroidectomy hypocalcaemia. The setting was a district general hospital in Hertfordshire covering a population of 500,000 people. A total of 196 patients who had had total or completion thyroidectomy during a five-year period were included in the study.

MATERIALS AND METHODS

The primary outcome measure was to determine the rate of biochemical and symptomatic hypocalcaemia in patients undergoing total or completion thyroidectomy. Secondary outcome measures assessed time taken for biochemical and clinical hypocalcaemia to resolve, whether malignancy affected the rate of hypocalcaemia and if removal of parathyroid glands during surgery were a predictor of hypocalcaemia.

RESULTS

The overall incidence of post-thyroidectomy hypocalcaemia (PTHC) within 24 hours was 21.4%. The incidence increased from 6 hours (13.8%) to 24 hours post-thyroidectomy (15.8%) and there was evidence of both transient and delayed PTHC within the first 24 hours. By 6 months post-surgery, 3.6% remained hypocalcaemic and required continual oral supplementation. Patients with benign thyroid disease had a higher risk of PTHC (P = 0.04) and patients younger than 50 years of age had a higher risk of symptomatic hypocalcaemia (P = 0.016). Other clinical factors including sex, type of surgery, neck dissection, oral calcium and/or vitamin D supplementation and inadvertent histological parathyroid gland excision were not associated with an increased incidence of PTHC or symptomatic hypocalcaemia.

CONCLUSIONS

Our audit shows that the rate of PTHC within our population was below the national average with higher risk in benign thyroid disease.

Clinicopathological characteristics of incidental parathyroidectomy after total thyroidectomy: The effect on hypocalcemia. A retrospective cohort study

BACKGROUND

The reported rate of incidental parathyroidectomy (IP) during total thyroidectomy varies between 6.4 and 31.1%. The aim of this study was to investigate the clinicopathological characteristics associated with IP.

MATERIALS AND METHODS

This is a retrospective cohort study which included 2556 patients who underwent total thyroidectomy between 2002 and 2012 at a single tertiary institution. Demographics, clinicopathological risk factors, and postoperative calcium levels were compared between IP and control group.

RESULTS

Incidental parathyroidectomy occurred in 18.3% of patients. IP patients had higher risk of postoperative biochemical (40.3% vs 17.3%, p < 0.001) and symptomatic hypocalcemia (14.3% vs 7.3%, p < 0.001) than no-IP group. Multivariate analysis showed malignancy, tumor size >10 mm, thyroid capsule invasion, extrathyroidal extension, lymph node metastases and central neck dissection, operation time, RLN injury, thyroid gland dimensions were independent risk factors for IP.

CONCLUSIONS

Our results indicate that patients with certain preoperative findings such as larger thyroid dimensions, diagnosis of malignancy and especially tumor >10 mm, extrathyroidal extension, and lymph node metastasis are at higher risk of IP and postoperative symptomatic hypocalcemia and these patients should be adequately informed and treated. Α meticulous intraoperative identification and the preservation of all parathyroid glands results in lower incidence of IP and postoperative hypocalcemia.

Effect of nerve monitoring on complications of thyroid surgery

OBJECTIVE:

The most frequent and critical complications of thyroid surgery are recurrent laryngeal nerve palsy and hypocalcemia. In first years of the 21st century, intraoperative neuromonitoring (IONM) was introduced as a new technique to avoid the recurrent laryngeal nerve (RLN) injury. However, the role and the benefits of IONM are still controversial. In this study, we aimed to compare the postoperative complication rates during thyroid surgery with IONM usage (Group 1) and conventional direct visual technique without IONM usage (Group 2).

METHODS:

We conducted retrospective review of all patients undergoing thyroid surgery in Lütfiye Nuri Burat State Hospital General Surgery Department between 2014 and 2016 years. Patients have been classified in to two groups: Group 1 and 2.

RESULTS:

Overall, 191 patients were included in the study; Group 1 comprised 79 patients and Group 2 comprised 112 patients. Unilateral RLN paralysis was observed in 7 patients in Group 1 (8.9%) and 15 patients in Group 2 (13.4%) without any significant difference between the groups (p=0.368). Hypocalcemia was encountered in 5 patients (6.3%) in Group 1 and 18 patients (16.1%) in Group 2; this difference was statistically significant (p=0.045). Other complications (such as hematoma and suture reaction) were not significantly different. Operation time was found to be significantly shorter in Group 1 (Mean time, 93.08 min) than in Group 2 (116.54 min) (p=0.03).

CONCLUSION:

Proven effect of IONM on RLN paralysis is still controversial. However, easy identification of RLN, which gives more confidence to surgeon, and shorter operation time may be factors to lower hypocalcemia rates.

A clinical pathway for the postoperative management of hypocalcemia after pediatric thyroidectomy reduces blood draws

OBJECTIVES

Postoperative calcium management is challenging following pediatric thyroidectomy given potential limitations in self-reporting symptoms and compliance with phlebotomy. A protocol was created at our tertiary children's institution utilizing intraoperative parathyroid hormone (PTH) levels to guide electrolyte management during hospitalization. The objective of this study was to determine the effect of a new thyroidectomy postoperative management protocol on two primary outcomes: (1) the number of postoperative calcium blood draws and (2) the length of hospital stay.

STUDY DESIGN

Institutional review board approved retrospective study (2010-2016).

METHODS

Consecutive pediatric total thyroidectomy and completion thyroidectomy ± neck dissection cases from 1/1/2010 through 8/5/2016 at a single tertiary children's institution were retrospectively reviewed before and after initiation of a new management protocol. All cases after 2/1/2014 comprised the experimental group (post-protocol implementation). The pre-protocol control group consisted of cases prior to 2/1/2014. Multivariable linear and Poisson regression models were used to compare the control and experimental groups for outcome measure of number of calcium lab draws and hospital length of stay.

RESULTS

53 patients were included (n = 23, control group; n = 30 experimental group). The median age was 15 years. 41 patients (77.4%) were female. Postoperative calcium draws decreased from a mean of 5.2 to 3.6 per day post-protocol implementation (Rate Ratio = 0.70, p < .001), adjusting for covariates. The mean number of total inpatient calcium draws before protocol initiation was 13.3 (±13.20) compared to 7.2 (±4.25) in the post-protocol implementation group. Length of stay was 2.1 days in the control group and 1.8 days post-protocol implementation (p = .29). Patients who underwent concurrent neck dissection had a longer mean length of stay of 2.32 days compared to 1.66 days in those patients who did not undergo a neck dissection (p = .02). Hypocalcemia was also associated with a longer mean length of stay of 2.41 days compared to 1.60 days in patients who did not develop hypocalcemia (p < .01).

CONCLUSIONS

The number of calcium blood draws was significantly reduced after introduction of a standardized protocol based on intraoperative PTH levels. The hospital length of stay did not change. Adoption of a standardized postoperative protocol based on intraoperative PTH levels may reduce the number of blood draws in children undergoing thyroidectomy.

[Not Available]

Parathormone (PTH), produced by parathyroid glands, is the main regulator of calcium homeostasis. Hypoparathyroidism (hypoPT), due to decrease of PTH production, is a rare disease. Symptoms are multiple, altering function of several organs and leading to a decrease of quality of life. Acquired etiologies, including thyroïdectomy, the main cause of hypoPT, can be distinguished from congenital etiologies, including genetic defects. HypoPT, which is classically treated by supplementation by calcium and active vitamin D, can now be treated by recombinant injection in certain indications as a poor control under classical therapy. Here are summarized current knowledge on etiologies, epidemiology, clinical manifestations and management of hypoPT.

Impact of pre-operative serum 25-hydroxyvitamin D on post-operative serum calcium in patients undergoing total thyroidectomy for benign goitre: retrospective study of 246 patients

OBJECTIVE

To determine whether pre-operative serum 25-hydroxyvitamin D has an impact on post-operative parathyroid hormone and serum calcium levels in patients undergoing total thyroidectomy for benign goitre.

METHODS

This single-centre, retrospective study comprised 246 unselected surgical patients who had undergone total thyroidectomy for bilateral, benign, multinodular goitre. The correlation between pre-operative serum 25-hydroxyvitamin D and post-operative serum parathyroid hormone and serum calcium was studied to determine whether low pre-operative serum 25-hydroxyvitamin D was predictive of post-operative hypocalcaemia.

RESULTS

Seventy-nine patients (32 per cent) had post-operative hypocalcaemia. Eighteen patients (7.32 per cent) experienced unintentional parathyroidectomy (1 parathyroid gland in 15 patients, 2 parathyroid glands in 3 patients). In univariate analysis, pre-operative serum 25-hydroxyvitamin D was not correlated with post-operative serum calcium (p = 0.69) or post-operative serum parathyroid hormone (p = 0.5804). Furthermore, in multivariate analysis, which took into account unintentional parathyroidectomy, no correlation was found (p = 0.33). Bilateral unintentional parathyroidectomy was statistically associated with post-operative hypocalcaemia (p = 0.032).

CONCLUSION

Pre-operative serum 25-hydroxyvitamin D did not appear to have any impact on post-operative serum calcium in patients undergoing total thyroidectomy for benign goitre.

Prolonged Duration of Surgery Predicts Postoperative Hypoparathyroidism among Patients Undergoing Total Thyroidectomy in a Tertiary Referral Centre

BACKGROUND

Postoperative hypoparathyroidism is a common complication following total thyroidectomy. The aim of this study was to investigate the incidence of both transient and permanent hypoparathyroidism in patients undergoing total thyroidectomy in a tertiary referral centre and, furthermore, to identify early predictive risk factors.

METHODS

Based on a single-institution retrospective review, we identified 582 patients who underwent total thyroidectomy between January 2010 and March 2015. Information on age, gender, pathological diagnosis, duration of surgery, autotransplantation of parathyroid glands, neck dissection, and experience and position of the surgeon was retrieved from the medical records. Furthermore, serum levels of parathyroid hormone and calcium were registered pre- and postoperatively and after 3 and 12 months.

RESULTS

The incidence of transient hypoparathyroidism during the first 24 h and 3 months after surgery was 47.8 and 17.8%, respectively. Furthermore, the incidence of permanent hypoparathyroidism 1 year after surgery was 10.7%. A prolonged duration of surgery was significantly associated with hypoparathyroidism. Moreover, autotransplantation of parathyroid glands was a significant predictor of transient hypoparathyroidism after 24 h and 3 months, but was not associated with permanent hypoparathyroidism.

CONCLUSIONS

Transient and permanent hypoparathyroidism is common among patients undergoing total thyroidectomy in a tertiary referral centre. A duration of surgery >120 min constitutes an independent risk factor due to the risk of ischaemic damage. Regain of function of devascularized parathyroid glands must be expected to last at least 1 year postoperatively. Furthermore, the recovery of autotransplanted parathyroid glands should not be evaluated within 1-3 months after surgery.

Postoperative IPTH compared with IPTH gradient as predictors of post-thyroidectomy hypocalcemia

OBJECTIVES/HYPOTHESIS

Predicting patients' risk for hypocalcemia after thyroidectomy may allow for same-day discharge. This study was designed to compare postoperative intact parathyroid hormone (IPTH) alone with percentage change in IPTH (IPTH gradient) in predicting post-thyroidectomy hypocalcemia.

STUDY DESIGN

Retrospective cohort study.

METHODS

Patients undergoing total thyroidectomy by the senior author from May 2015 to May 2016 were included. Serum IPTH was measured preoperatively and 1 hour postoperatively, and IPTH gradient was calculated. Postoperative hypocalcemia was mild (≥8.0, <8.4) or severe (<8.0 and/or hypocalcemic symptoms). Postoperative IPTH and IPTH gradient were compared with hypocalcemia using logistic regression. Receiver operating characteristic analysis of IPTH measures as predictors of hypocalcemia was performed, and the area under the curve (AUC) was calculated.

RESULTS

Overall, 119 patients were included. Forty-seven percent of the patients developed postoperative hypocalcemia, including 26 (22%) with mild and 30 (25%) with severe hypocalcemia. Thirteen patients had hypocalcemic symptoms. Median IPTH gradient and postoperative IPTH each differed significantly by category of hypocalcemia (P < .001). Higher IPTH gradient was significantly associated with odds of severe and symptomatic hypocalcemia (adjusted odds ratio [aOR]: 1.21, 95% confidence interval [CI]: 1.06-1.39 and aOR: 1.34, 95% CI: 1.05-1.71 per 10% increase), whereas lower postoperative IPTH was not (aOR: 1.27, 95% CI: 0.95-1.68 and aOR: 1.44, 95% CI: 0.90-2.31 per 10 pg/mL decrease). The AUC for predicting severe hypocalcemia was nonsignificantly higher for IPTH gradient than postoperative IPTH (AUC = 0.77 vs. 0.69, P = .10). The AUC for predicting symptomatic hypocalcemia was significantly higher for IPTH gradient (AUC = 0.75 vs. 0.72, P = .03).

CONCLUSIONS

Our results suggest that the IPTH gradient may be more useful than postoperative IPTH alone in predicting risk of post-thyroidectomy hypocalcemia.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:769-774, 2018.

Indications and extent of central neck dissection for papillary thyroid cancer: An American Head and Neck Society Consensus Statement

BACKGROUND

The primary purposes of this interdisciplinary consensus statement were to review the relevant indications for central neck dissection (CND) in patients with papillary thyroid cancer (PTC) and to outline the appropriate extent and relevant techniques required to accomplish a safe and effective CND.

METHODS

A writing group convened by the American Head and Neck Society (AHNS) Endocrine Committee was tasked with identifying the important clinical elements to consider when managing the central neck compartment in patients with PTC based on available evidence in the literature, and the group's collective experience. The position statement paper was then submitted to the full Endocrine Committee, Education Committee, and AHNS Council.

RESULTS

This consensus statement was developed to inform the clinical decision-making process when managing the central neck compartment in patients with PTC from the AHNS. This document is intended to provide clarity through definitions as well as a basic guideline from which to manage the central neck. It is our hope that this improves the quality and reduces variation in management of the central neck, facilitates communication, and furthers research for patients with thyroid cancer.

CONCLUSION

This represents, in our opinion, contemporary optimal surgical care for this patient population and is endorsed by the American Head and Neck Society. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1269-1279, 2017.

Early discharge after total thyroidectomy: a retrospective feasibility study

AIM

The continued hospitalization after total thyroidectomy is often due to the onset of hypocalcemic complications more than 24 hours after surgery. So it would be important to predict which patients will not develop the hypocalcemic complication to discharge them early. This was the aim of our study.

PATIENTS AND METHODS

Our retrospective study was conducted on 327 consecutive thyroidectomized patients, operated on for benign and malignant diseases. We evaluated the values of preoperative serum calcium levels (Cal0) and of the first postoperative day (Cal1) and two new variables were calculated (dCal and dCaln). The same thing was made on a subgroup of 111 patients in whom also parathiroyd hormone (PTH) values were detected. Statistical analysis was performed with the goal of determining if we could establish a safe criterion for discharge at 24 hours after surgery and if there is a correlation between suitability for discharge and diagnosis.

RESULTS

As to discharge, the predictive power of the discriminant function applied was significant both on the total of patients and in the subgroup of 111 patients, but it was clinically unacceptable because it would expose us to a 21% to 27% error rate. It is not possible to identify a threshold, below which to consider patients surely dischargeable. The diagnosis does not appear correlated with the suitability for discharge.

CONCLUSION

On the basis of serum calcium and PTH levels in the first postoperative day, it is impossible to predict which patients can be discharged 24 hours after surgery without incurring in hypocalcemic complications.

Risk of Complications after Thyroidectomy and Parathyroidectomy: A Case Series with Planned Chart Review

OBJECTIVE

To develop a predictive model for the risk of complications after thyroid and parathyroid surgery.

STUDY DESIGN

Case series with planned chart review of patients undergoing surgery, 2007-2013.

SETTING

Kaiser Permanente Northern California and Kaiser Permanente Southern California.

SUBJECTS AND METHODS

Patients (N = 16,458) undergoing thyroid and parathyroid procedures were randomly assigned to model development and validation groups. We used univariate analysis to assess relationships between each of 28 predictor variables and 30-day complication rates. We subsequently entered all variables into a recursive partitioning decision tree analysis, with P < .05 as the basis for branching.

RESULTS

Among patients undergoing thyroidectomies, the most important predictor variable was thyroid cancer. For patients with thyroid cancer, additional risk predictors included coronary artery disease and central neck dissection. For patients without thyroid cancer, additional predictors included coronary artery disease, dyspnea, complete thyroidectomy, and lobe size. Among patients undergoing parathyroidectomies, the most important predictor variable was coronary artery disease, followed by cerebrovascular disease and chronic kidney disease. The model performed similarly in the validation groups.

CONCLUSION

For patients undergoing thyroid surgery, 7 of 28 predictor variables accounted for statistically significant differences in the risk of 30-day complications; for patients undergoing parathyroid surgery, 3 variables accounted for significant differences in risk. This study forms the foundation of a parsimonious model to predict the risk of complications among patients undergoing thyroid and parathyroid surgery.

Association between Magnesium Disorders and Hypocalcemia following Thyroidectomy

OBJECTIVE

To identify factors associated with postoperative hypocalcemia after thyroid surgery and to understand the relationship among hypocalcemia, length of hospitalization, and costs of care.

STUDY DESIGN

Retrospective database analysis.

METHODS

Discharge data from the Nationwide Inpatient Sample for 620,744 patients who underwent thyroid surgery from 2001 to 2010 were analyzed through cross-tabulations and multivariate regression modeling. Hypocalcemia, length of stay, and costs were examined as dependent variables. Secondary independent variables included magnesium and phosphate metabolism disorders, vitamin D deficiency, menopause, sex, extent of surgery, malignancy, and surgeon volume.

RESULTS

Hypocalcemia was reported in 6% of patients and was significantly more common for the following variables: women, age <65 years, patients from the Northeast, total thyroidectomy ± neck dissection patients, low-volume surgical care, malignancy, recurrent laryngeal nerve injury, and patients with disorders of magnesium or phosphate metabolism (P < .001). Magnesium and phosphate disorders were present in <1% of patients. Magnesium disorders were significantly more likely for patients with hypocalcemia (7%; P < .001), and hypocalcemia was present in 52% of patients with magnesium disorders (P < .001). On multiple logistic regression analysis, the odds of hypocalcemia were greatest for patients with magnesium disorders (odds ratio, 12.71; 95% confidence interval, 8.59-18.82). This relationship was not attenuated by high-volume surgical care. Hypocalcemia and magnesium disorders were both associated with increased length of stay and costs, with a greater effect for magnesium disorders than for hypocalcemia (P < .001).

CONCLUSIONS

Disorders of magnesium metabolism are an independent risk factor for postthyroidectomy hypocalcemia and are associated with significantly increased costs and length of stay.

Factors affecting postoperative hypocalcemia after thyroid surgery: Importance of incidental parathyroidectomy

OBJECTIVE

The present study evaluated effects of incidental parathyroidectomy, surgical technique, and presence of thyroiditis or hyperthyroidism on occurrence of postoperative persistent or transient hypocalcemia.

METHODS

Patients who underwent thyroidectomy at İstanbul Medeniyet University between 2013 and 2015 were included in the study. Patient information, postoperative serum calcium levels, and pathology reports were investigated retrospectively. Group 1 was made up of patients who were found to have hypocalcemia (calcium ≤8.5 mg/dL) according to postoperative serum level and normocalcemic patients were placed in Group 2. Groups were compared statistically in terms of rate of incidental parathyroidectomy, surgical technique, and presence of thyroiditis or hyperthyroidism.

RESULTS

Mean age was 49.8±12.8 years (range: 20-88). A total of 417 patients were included in the study, 74 (17.7%) were male and 343 (82.3%) were female. Group 1 consisted of 205 (49.2%) patients who had hypocalcemia according to postoperative serum level, and remaining 212 (50.8%) patients were placed in Group 2. In Group 1, 38 (18.5%) patients had incidental parathyroidectomy, and with only 18 (8.5%) patients in Group 2, a statistically significant relationship was found between incidental parathyroidectomy and hypocalcemia (p=0.003). There was no statistically significant difference in terms of presence of thyroiditis or hyperthyroidism between groups. There was statistically significant decrease in postoperative hypocalcemia rate in patients with lobectomy compared to patients with bilateral total thyroidectomy or central neck dissection (p<0.01).

CONCLUSION

Risk of postoperative hypocalcemia may be reduced with lobectomy for selected patients. In addition, delicate dissection during thyroidectomy is important in order to protect parathyroid glands and prevent hypocalcemia.