Better consenting for thyroidectomy: who has an increased risk of postoperative hypocalcaemia?

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Role of perioperative parathormone hormone level assay after total thyroidectomy as a predictor of transient and permanent hypocalcemia: Prospective study

Background

The researchers are trying to evaluate the measurement of: Intact parathyroid hormone (iPTH) and serum total calcium (sCa) levels for predicting hypocalcemia after total thyroidectomy (TT).

Methods

The sample of this single center prospective study consists of (100) patients, where (77) females and (23) males with an age range between (28) and (65) (the mean level is, 48.17 ± 6.54). These selected patients underwent total thyroidectomy (TT) in the general surgery department, Benha university hospital from the period of June 2019 to February 2020. Levels of sCa and iPTH were measured aat several times preoperatively, 10 min, 48 h, 3, 6, 9 months, and 1 year after being after gone TT.

Results

Among the entire study sample, 23 patients (23%) developed transient hypoparathyroidism and hypocalcemia (˂8.5 mg/dl), none of them developed permanent hypoparathyroidism and hypocalcemia. The cut-off point of PTH has been 10 min after TT was at 23 pg/mL as it was the best compromise between sensitivity and specificity for predicting hypocalcaemia. It has been found that Patients who have a PTH greater than 23 pg/mL can be discharged safely after 24 h. Patients who have PTH of less than 23 pg/mL were observed for an additional 24 h, and the study found that timely treatment initiation is recommended. A PTH ˂ 10 pg/mL measured at 48 h after surgery had a sensitivity, specificity as well as an accuracy of 100%, for predicting hypocalcemia after TT. The accuracy of a single PTH concentration at 48 h was useful for predicting hypocalcemia [Area under receiver–operator characteristic curve (AUC) 1; confidence interval (CI), 95%, 0.85–0.94].

Conclusion

Patients with iPTH ˂ 10 pg/mL, and sCa levels ˂ 7.4 mg/dL are at higher risk of developing hypoparathyroidism and hypocalcemia after TT.

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Incidence of Post-thyroidectomy transient hypoparathyroidism ranges between 0.3 and 49%, while permanent hypoparathyroidism is 13%.

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Incidence of hypocalcemia following total thyroidectomy ranging between 3% and 40% and is usually transient, while permanent hypocalcemia is ≤ 2%.

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Post-thyroidectomy PTH accurately predict hypocalcemia.

A territory-wide assessment of the incidence of persistent hypoparathyroidism after elective thyroid surgery and its impact on new fracture risk over time

BACKGROUND

Although persistent (≥6 months) postoperative hypoparathyroidism is often believed to be rare after elective total thyroidectomy, we hypothesized a higher incidence in the community and that patients with persistent postoperative hypoparathyroidism may have a higher fracture risk. A population-based analysis was performed using an electronic health database to address these issues.

METHODS

All elective total thyroidectomies performed in 14 major hospitals across the territory over 20 years were analyzed. Persistent postoperative hypoparathyroidism was defined by the requirement of oral calcium and vitamin D shortly postoperatively and continued for ≥6 months. Those with albumin-corrected calcium <1.90 mmol/L on ≥1 occasion beyond 1 year postoperation were considered suboptimally controlled. Patients were followed until an index fracture, death, or the time of analysis, whichever was earlier. Multivariable Cox regression analysis was used to identify clinical predictors for fractures.

RESULTS

Among 4,123 eligible patients, 460 patients (11.2%) had persistent postoperative hypoparathyroidism. Over a median of 10.3 years, 126 patients suffered from a new fracture (2.77 per 1,000 person-years). There was no difference in fracture events between patients with and without persistent postoperative hypoparathyroidism (P = .761). Subgroup analyses according to the adequacy of persistent postoperative hypoparathyroidism control did not reveal significant differences in fracture events. Age, female, history of fall, and diabetes independently predicted post-thyroidectomy fractures.

CONCLUSION

Persistent postoperative hypoparathyroidism appeared to be a more common complication in the community after elective total thyroidectomy than previously thought. We did not observe a significant difference in fracture risk between patients with and without persistent postoperative hypoparathyroidism. The impact of persistent postoperative hypoparathyroidism control on fracture risk remained to be determined.

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

OBJECTIVE

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

RESULTS

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

CONCLUSION

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

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.

Hypocalcaemia following laryngectomy: prevalence and risk factors

OBJECTIVES

To establish the prevalence of hypocalcaemia following laryngectomy and demonstrate that total thyroidectomy is a risk factor.

METHODS

A retrospective cohort study was conducted that included all patients who underwent total laryngectomy from 1st January 2006 to 1st August 2017. Exclusion criteria were: pre-operative calcium derangement, previous thyroid or parathyroid surgery, concurrent glossectomy, pharyngectomy, or oesophagectomy.

RESULTS

Ninety patients were included. Sixteen patients had early hypocalcaemia (18 per cent), seven had protracted hypocalcaemia (8 per cent) and six had permanent hypocalcaemia (10 per cent). Exact logistic regression values for hypocalcaemia following total thyroidectomy compared to other patients were: early hypocalcaemia, odds ratio = 15.5 (95 per cent confidence interval = 2.2-181.9; model p = 0.002); protracted hypocalcaemia, odds ratio = 13.3 (95 per cent confidence interval = 1.5-117.1; model p = 0.01); and permanent hypocalcaemia, odds ratio = 22.7 (95 per cent confidence interval = 1.9-376.5; model p = 0.005).

CONCLUSION

This is the largest study to investigate the prevalence of hypocalcaemia following laryngectomy and the first to include follow up of longer than three months. Total thyroidectomy significantly increased the risk of hypocalcaemia at all time frames and independent of other variables.

Thyroidectomy in elderly patients aged ≥70 years

Worldwide, the indications for thyroid surgery have been continuously extended among elderly patients in the last 20 years. The balance between treatment indication and surgical risk is certainly an interesting topic for every thyroid surgeon. This paper is a review of recent literature from January 2005 up to April 2017. We analyzed three principal subjects: indications for surgical treatment, medical complications and surgical complications. We can summarize the conclusions of our analysis, stating that age could not be considered as an absolute factor, but in relation to the comorbidities and the general clinical condition of the patient. Special risk indices dedicated to geriatric patients could be very useful in order to facilitate the decision-making process; however, relying on the current knowledge, we could state that there is value in providing surgery to geriatric patients in highly specialized and high-volume centers, where access to technology and its systematic use, coupled with surgeons' experience, could certainly avail the geriatric patient management.

How reliably can computed tomography predict thyroid invasion prior to laryngectomy?

OBJECTIVES/HYPOTHESIS

There is little evidence to support the removal of thyroid tissue during total laryngectomy. Although oncological control of the tumor is the priority, thyroidectomy can lead to hypothyroidism and hypoparathyroidism. This study aimed to test the usefulness of preoperative computed tomography in predicting histological invasion of the thyroid.

STUDY DESIGN

Ambispective cohort study.

METHODS

All patients undergoing total laryngectomy for squamous cell carcinoma at one center from 2006 to 2016 were included. Data were recorded prospectively as part of the patients' standard care, but were collated retrospectively, giving this study an ambispective design. The histology report for thyroid invasion was taken as the gold standard. The computed tomography report was categorized by invasion of tumor into intralaryngeal, laryngeal cartilage involvement, and extralaryngeal tissues.

RESULTS

Seventy-nine patients were included. Nine patients had thyroid involvement on histology, translating to an incidence of 11.29% in this population. The positive predictive value for cartilage involvement on computed tomography for thyroid invasion was 52.9% (95% confidence interval [CI]: 28.5%-76.1%) and the negative predictive value was 100% (95% CI: 92.7%-100%).The positive predictive value for extralaryngeal spread on computed tomography for thyroid involvement was 100% (95% CI: 62.9%-100%), and the negative predictive value was also 100% (95% CI: 93.5%-100%).

CONCLUSIONS

This study has shown that preoperative computed tomography is an effective method of ruling out thyroid gland invasion. The absence of extralaryngeal spread on computed tomography has been shown to be the most useful finding, with a high negative predictive value and a narrow 95% CI.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1099-1102, 2018.