Predicting the need for calcium and calcitriol supplementation after total thyroidectomy: results of a prospective, randomized study

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.

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.

Early parathyroid hormone (PTH) level as a predictor of post-surgical hypoparathyroidism

INTRODUCTION

Post-operative hypocalcemia and postoperative persistent hypoparathyroidism remain the most common complications after thyroidectomy. Many approaches have been developed to prevent them, but actually, a common protocol is not yet individuated.

MATERIALS AND METHODS

We retrospectively analyzed the results of a prospectively collected database. We dosed PTH preoperatively and 4 h after surgery (PTH_4); calcium was evaluated preoperatively, on the first (I_POD) and on the second postoperative day (II_POD). Hypocalcemia was defined when calcium <8 mg/dl. PTH_4 and I_POD calcium serum levels are identified to predict postoperative hypocalcemia.

RESULTS

Three hundred and forty-eight patients were enrolled, 37 patients resulted as hypocalcemic on I_POD and 41 on the II_POD. PTH_4 is related to I_POD (p < 0.001, r = 0.45) and II_POD (p < 0.001, r = 0.44) calcemia. PTH_4-cut-off predicting I_POD hypocalcemia was 10.50 pg/ml (sensitivity: 78.7%, specificity: 72.7%). A PTH_4 value of 11.5 pg/ml is able to predict hypocalcemia during II_POD (sensitivity: 76.5%, specificity: 69.2%). We set up a combined test to predict II_POD hypocalcemia, using PTH_4 and I_POD calcium (sensitivity: 77.8%, specificity: 89.9%).

CONCLUSION

This research shows the association between PTH_4 and postoperative hypocalcemia. The PTH_4 cut-off to predict I_POD-hypocalcemia was 10.5 pg/ml. We analyzed the calcemia trend during the postoperative period and we realized a combined test using PTH_4 and I_POD-calcemia. This test improves the accuracy of the previous test. Further studies, in particular multicentric, with a larger sample are necessary to validate the combined model.

Assessing Symptomatic Hypocalcemia Risk After Total Thyroidectomy: A Prospective Study

Introduction  The most common postoperative complication of total thyroidectomy is hypocalcemia, usually monitored using serum parathyroid hormone and calcium values. Objective  To identify the most accurate predictors of hypocalcemia, construct a risk assesment algorithm and analyze the impact of using several calcium correction formulas in practice. Methods  A prospective, single-center, non-randomized longitudinal cohort study on 205 patients undergoing total thyroidectomy. Parathyroid hormone, serum, and ionized calcium were sampled post-surgery, with the presence of symptomatic or laboratory-verified asymptomatic hypocalcemia designated as primary outcome measures. Results  Parathyroid hormone sampled on the first postoperative day was the most sensitive predictor of symptomatic hypocalcemia development (sensitivity 80.22%, cut-off value ≤2.03 pmol/L). A combination of serum calcium and parathyroid concentration sampled on the first postoperative day predicted the development of hypocalcemia during recovery with the highest sensitivity and specificity (94% sensitivity, cut-off ≤2.1 mmol/L, and 89% specificity, cut-off ≤1.55 pmol/L, respectively). The use of algorithms and correction formulas did not improve the accuracy of predicting symptomatic or asymptomatic hypocalcemia. Conclusions  The most sensitive predictor of symptomatic hypocalcemia present on the fifth postoperative day was PTH sampled on the first postoperative day. The need for algorithms and correction formulas is limited.

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.

Accuracy of Serum Parathyroid Hormone Measured on the Early Morning of the First Postoperative Day in Predicting Clinically Significant Post-Total Thyroidectomy Hypocalcemia

INTRODUCTION

Clinical hypocalcemia (CH) following total thyroidectomy (TT) is a potentially life-threatening condition if left untreated. This study aimed at evaluating the accuracy of parathyroid hormone (PTH) measured in the early morning of the first postoperative day (POD-1) in predicting CH, and determining the cutoff values of PTH that can predict the development of CH.

METHODS

We performed a retrospective review of patients undergoing TT between February 2018 and July 2022. Serum PTH, calcium, and albumin levels were measured on morning (6-8 AM) of postoperative day one (POD-1), and serum calcium level was measured from POD-2 onwards. We performed ROC curve analysis to determine the accuracy of PTH in predicting postoperative CH, and cutoff values of PTH to predict CH.

RESULTS

Ninety-one patients, 52 (57.1%) with benign and 39 (42.9%) with malignant goiter were included. The incidence of biochemical, and clinical hypocalcemia was 24.2% and 30.8%, respectively. In our study serum, PTH measured in the early morning of first postoperative day following TT was found to have good accuracy (AUC = .88) in predicting CH. A PTH value of ≥27.15 pg/mL was found to have a 96.4% sensitivity in ruling out CH, while a serum PTH value <10.65 pg/mL had a specificity of 95.2% in predicting CH.

DISCUSSION

Patients with a serum PTH value of ≥27.15 pg/mL can be discharged without any supplements, those with PTH <10.65 pg/mL should be started on calcium and calcitriol supplements, while patients having PTH values between 10.65 and 27.15 pg/mL should be monitored for the development of signs and/or symptoms of hypocalcemia.

Impact of autofluorescence for detection of parathyroid glands during thyroidectomy on postoperative parathyroid hormone levels: parallel multicentre randomized clinical trial

BACKGROUND

Techniques for autofluorescence have been introduced to visualize the parathyroid glands during surgery and to reduce hypoparathyroidism after thyroidectomy.

METHODS

This parallel multicentre RCT investigated the use of Fluobeam® LX to visualize the parathyroid glands by autofluorescence during total thyroidectomy compared with no use. There was no restriction on the indication for surgery. Patients were randomized 1 : 1 and were blinded to the group allocation. The hypothesis was that autofluorescence enables identification and protection of the parathyroid glands during thyroidectomy. The primary endpoint was the rate of low parathyroid hormone (PTH) levels the day after surgery.

RESULTS

Some 535 patients were randomized, and 486 patients received an intervention according to the study protocol, 246 in the Fluobeam® LX group and 240 in the control group. Some 64 patients (26.0 per cent) in the Fluobeam® LX group and 77 (32.1 per cent) in the control group had low levels of PTH after thyroidectomy (P = 0.141; relative risk (RR) 0.81, 95 per cent c.i. 0.61 to 1.07). Subanalysis of 174 patients undergoing central lymph node clearance showed that 15 of 82 (18 per cent) in the Fluobeam® LX group and 31 of 92 (33 per cent) in the control group had low levels of PTH on postoperative day 1 (P = 0.021; RR 0.54, 0.31 to 0.93). More parathyroid glands were identified during operation in patients who had surgery with Fluobeam® LX, and fewer parathyroid glands in the surgical specimen on definitive histopathology. No specific harm related to the use of Fluobeam® LX was reported.

CONCLUSION

The use of autofluorescence during thyroidectomy did not reduce the rate of low PTH levels on postoperative day 1 in the whole group of patients. It did, however, reduce the rate in a subgroup of patients. Registration number: NCT04509011 (http://www.clinicaltrials.gov).

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Parathyroid hormone-driven algorithms after thyroid surgery: Not one-size-fits-all

BACKGROUND

Underreported variation in parathyroid hormone (PTH) assays exists. Using quality improvement methods, we aimed to develop an institution-specific PTH-based protocol to predict hypocalcemia after thyroidectomy.

METHODS

We retrospectively reviewed patients who underwent total/completion thyroidectomy. A receiver operating curve (ROC) determined postoperative PTH cut-offs predictive of hypocalcemia. The stakeholders developed PTH-driven calcium management guidelines. Post-implementation outcomes were prospectively measured.

RESULTS

Pre-implementation, 95 patients were assessed. PTH ≤1.5 pmol/L (14.1 pg/ml) predicted hypocalcemia (96%sensitivity), and ≥2.8 pmol/L (26.4 pg/ml) predicted normocalcemia (99%specificity) (area under curve = 0.97, SEM = 0.018). PTH on the day of and morning after surgery were identically predictive. Post-implementation, 64 patients were assessed. Hypocalcemia occurred with PTH >2.8 pmol/L in 2 cases (3.1%). Calcium over-prescribing decreased from 13.7% to 3.1% (p = 0.06). Length of stay (LOS) > 2 nights decreased from 13% to 3.1% (p = 0.05).

CONCLUSION

A PTH-driven calcium management protocol post-thyroidectomy effectively reduces unnecessary calcium replacement and LOS. Given the variability in PTH assays, each institution may need to use individual cut-offs.

Etiology and Pathophysiology of Hypoparathyroidism: A Narrative Review

The approach utilized a systematic review of the medical literature executed with specifically designed criteria that focused on the etiologies and pathogenesis of hypoparathyroidism. Enhanced attention by endocrine surgeons to new knowledge about parathyroid gland viability are reviewed along with the role of intraoperative parathyroid hormone (ioPTH) monitoring during and after neck surgery. Nonsurgical etiologies account for a significant proportion of cases of hypoparathyroidism (~25%), and among them, genetic etiologies are key. Given the pervasive nature of PTH deficiency across multiple organ systems, a detailed review of the skeletal, renal, neuromuscular, and ocular complications is provided. The burden of illness on affected patients and their caregivers contributes to reduced quality of life and social costs for this chronic endocrinopathy. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Evaluation and Management of Hypoparathyroidism Summary Statement and Guidelines from the Second International Workshop

This clinical practice guideline addresses the prevention, diagnosis, and management of hypoparathyroidism (HypoPT) and provides evidence-based recommendations. The HypoPT task forces included four teams with a total of 50 international experts including representatives from the sponsoring societies. A methodologist (GG) and his team supported the taskforces and conducted the systematic reviews. A formal process following the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology and the systematic reviews provided the structure for seven of the guideline recommendations. The task force used a less structured approach based on narrative reviews for 20 non-GRADEd recommendations. Clinicians may consider postsurgical HypoPT permanent if it persists for >12 months after surgery. To predict which patients will not develop permanent postsurgical HypoPT, we recommend evaluating serum PTH within 12 to 24 hours post total thyroidectomy (strong recommendation, moderate quality evidence). PTH > 10 pg/mL (1.05 pmol/L) virtually excludes long-term HypoPT. In individuals with nonsurgical HypoPT, genetic testing may be helpful in the presence of a positive family history of nonsurgical HypoPT, in the presence of syndromic features, or in individuals younger than 40 years. HypoPT can be associated with complications, including nephrocalcinosis, nephrolithiasis, renal insufficiency, cataracts, seizures, cardiac arrhythmias, ischemic heart disease, depression, and an increased risk of infection. Minimizing complications of HypoPT requires careful evaluation and close monitoring of laboratory indices. In patients with chronic HypoPT, the panel suggests conventional therapy with calcium and active vitamin D metabolites as first-line therapy (weak recommendation, low-quality evidence). When conventional therapy is deemed unsatisfactory, the panel considers the use of PTH. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

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.

How Long Does It Take to Regain Normocalcaemia in the Event of Postsurgical Hypoparathyroidism? A Detailed Time Course Analysis

Background: Postsurgical hypoparathyroidism (PH) is the most common side effect of bilateral thyroid resections. Data regarding the time course of recovery from PH are currently unavailable. Therefore, a detailed analysis of the time course of PH recovery and conditions associated with rapid recovery was conducted. Methods: This is a retrospective analysis of prospectively documented data. Patients with biochemical signs of PH or need for calcium supplementation were followed-up for 12 months. Logistic regression analyses were used to identify covariates of early as opposed to late recovery from PH. Results: There were 1097 thyroid resections performed from 06/2015 to 07/2016 with n = 143 PH. Median recovery time was 8 weeks and six patients (1.1% of total thyroid resections) required calcium supplementation > 12 months. Recovery of PH within 4 and 12 weeks was characterized by high PTH levels on the first postoperative day (4 weeks: OR 1.13, 95% CI 1.06−1.20; 12 weeks: OR 1.08, 95%CI 1.01−1.16). Visualization of all PTGs emerged as an independent predictor of recovery within 12 months (OR 2.32, 95% CI 1.01−4.93) and 24 weeks (OR 2.69, 95% CI 1.08−6.69). Conclusion: In the setting of specialized high-volume endocrine surgery, permanent PH is rare. However, every second patient will require more than 2 months of continued medical surveillance. Early recovery was associated with only moderately decreased postsurgical PTH-levels. Successful late recovery appeared to be associated with the number of parathyroid glands visualized during surgery.

Early Postoperative Parathormone and Calcium as Prognostic Factors for Postoperative Hypocalcemia

BACKGROUND

Postoperative hypocalcemia is one of the most common complications after total thyroidectomy. Parathormone (PTH) and calcium levels, measured several hours after surgery, have been suggested as valuable markers for detecting patients at risk for post-thyroidectomy hypocalcemia. We aimed to determine if early post-surgery PTH and calcium levels can be used for the early identification of patients at risk for symptomatic hypocalcemia.

METHODS

PTH and calcium were measured before surgery and at 10 min and 4 h post-thyroidectomy, in 77 patients. Performance characteristics of PTH and calcium levels and their post/pre-surgery ratios were calculated.

RESULTS

Four-hour calcium was a sensitive (93.75%) but not specific (67.61%) indicator of patients at risk for symptomatic hypocalcemia. The 4-h/pre-surgery PTH ratio was the most accurate (90.81%) and the most specific (94.37%) test to identify patients at risk. Serum calcium at 4-h, 4-h/pre-surgery PTH ratio, and PTH at 10 min post-surgery had the higher diagnostic odds ratios (50.86, 32.85, and 29.04, respectively). The 4-h/pre-surgery PTH ratio also had the highest (0.694) Youden's J statistic.

CONCLUSIONS

Low serum calcium levels 4 h after thyroidectomy and the 4-h/pre-surgery PTH ratio could be valuable additions to everyday clinical practice in post-thyroidectomy patients.

Predictive value of postoperative day 1 parathyroid hormone levels for early and late hypocalcaemia after thyroidectomy

PURPOSE

Early parathyroid hormone (PTH) levels after total thyroidectomy can predict patients at low risk of hypocalcaemia who can be discharged early without calcium supplementation. For centres without facility to perform early PTH levels, PTH levels sent on the first postoperative day (POD1) may be an alternative. However, there is less data regarding optimal cut-off PTH levels for POD1 discharge.

METHODS

Retrospective review of prospective database of thyroid operations between September 2009 and February 2020 at tertiary referral centre. Main outcome measure was symptomatic hypocalcaemia.

RESULTS

Five hundred seventy patients undergoing total (521) or completion thyroidectomy with POD1 PTH levels available were included. Among patients with POD1 PTH levels ≥ 20 pg/ml and POD1 calcium ≥ 2.0 mmol/l, the incidence of symptomatic hypocalcaemia was 1% (3/300), and need for intravenous calcium 0.3% (1/300). For POD1 PTH levels 15-19 pg/ml and POD1 calcium ≥ 2.0 mmol/l, the incidence of symptomatic hypocalcaemia and need for intravenous calcium was 5.4% (3/55). For PTH levels 10-14 pg/ml and calcium ≥ 2.0 mmol/l, the incidence of symptomatic hypocalcaemia and need for intravenous calcium was 11.7% (7/60). The risk of permanent hypoparathyroidism was < 1% for POD1 PTH levels ≥ 15 pg/ml; 5.4% for levels 10-14 pg/ml; and 19.8% for levels < 10 pg/ml.

CONCLUSIONS

POD1 PTH levels ≥ 15 pg/ml along with calcium ≥ 2.0 mmol/l are associated with low risk of symptomatic hypocalcaemia, and represent a safe criterion for discharge of most patients without calcium supplementation. For certain patient groups, a higher threshold of 20 pg/ml could be considered.

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.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Etiology and Diagnosis of Permanent Hypoparathyroidism after Total Thyroidectomy

Postoperative parathyroid failure is the commonest adverse effect of total thyroidectomy, which is a widely used surgical procedure to treat both benign and malignant thyroid disorders. The present review focuses on the scientific gap and lack of data regarding the time period elapsed between the immediate postoperative period, when hypocalcemia is usually detected by the surgeon, and permanent hypoparathyroidism often seen by an endocrinologist months or years later. Parathyroid failure after thyroidectomy results from a combination of trauma, devascularization, inadvertent resection, and/or autotransplantation, all resulting in an early drop of iPTH (intact parathyroid hormone) requiring replacement therapy with calcium and calcitriol. There is very little or no role for other factors such as vitamin D deficiency, calcitonin, or magnesium. Recovery of the parathyroid function is a dynamic process evolving over months and cannot be predicted on the basis of early serum calcium and iPTH measurements; it depends on the number of parathyroid glands remaining in situ (PGRIS)—not autotransplanted nor inadvertently excised—and on early administration of full-dose replacement therapy to avoid hypocalcemia during the first days/weeks after thyroidectomy.

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.

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.

Early Discharge and Selective Calcium Supplementation after Thyroidectomy Based on Post-Operative Day 1 Parathormone and Calcium Level: A Prospective Study

AIM

This study aimed to evaluate a protocol using post thyroidectomy parathyroid hormone (PTH) levels on the day after surgery to facilitate early discharge of patients.

METHODS

This prospective observational study was done in Christian Medical College, India over 1 year with 125 consecutive patients who had serum PTH and calcium values measured in the morning following thyroidectomy/first postoperative day (D1). Patients with no symptoms and signs of hypocalcemia and with serum calcium ≥8 mg/dL and PTH ≥6 pg/ml according to the protocol were discharged without supplements on D1. Patients were followed up and tested for a week after surgery in the outpatient clinic to assess hypocalcemia and readmission rates.

RESULTS

Seventy five patients (60%) could be discharged early on D1without calcium supplementation; only one patient had mild hypocalcemia symptoms managed with oral calcium supplements during outpatient follow-up within 1 week and none who followed the protocol required readmission. Temporary biochemical hypocalcemia was encountered in 36 patients (28.8%) including symptomatic hypocalcemia in 13 patients (10.4%). Among the 36 patients with hypocalcemia, 26 patients (72.2%) had a PTH level <6 pg/ml. Three patients required intravenous calcium infusion to correct hypocalcemia. Sensitivity, specificity and positive predictive value, and ROC of PTH 6 pg/ml in predicting hypocalcemia were 70.5%, 94.5% and 83.3%, 0.86, respectively. The low PTH could also guide early supplementation of calcium and all the severe hypocalcemia patients had PTH lower than the cut off of 6 pg/ml.

CONCLUSION

A PTH and calcium-based protocol can be effectively used for early discharge of thyroidectomy patients the day after surgery without calcium supplementation. The compliance of the patient for early discharge was good.

Perioperative Management and Outcomes of Hyperthyroid Patients Unable to Tolerate Antithyroid Drugs

BACKGROUND

Prior to thyroidectomy for hyperthyroidism, it is recommended that patients are managed with antithyroid drugs (ATDs) and rendered euthyroid to decrease the risk of thyroid storm. However, not all patients tolerate ATD and the risk of thyroid storm during thyroidectomy in these patients is unclear. Therefore, the aim of this study was to compare the management and outcomes of hyperthyroid patients that were on ATDs prior to surgery to those who were not.

STUDY DESIGN

A prospectively maintained, single-institution database was queried for all hyperthyroid patients who were initially treated with ATDs and underwent thyroidectomy from January 1, 2012, to June 18, 2018. Patients were divided into two groups: (1) those on ATDs at surgery (ATD group) and (2) those who could not tolerate and stopped ATDs prior to surgery (no-ATD group). Demographic and clinical data were collected. Primary outcomes were readmissions/emergency department visits and postoperative complications within 30 days of thyroidectomy.

RESULTS

Of the 248 patients, 231 were in the ATD group and 17 (7%) were in the no-ATD group. There were no mortalities or thyroid storm events in either group. There was no difference in Clavien-Dindo Grade 2 or 3 complications between the two groups. There were no ED visits or 30-day readmissions in the no-ATD group compared to 17 (7%) events in the ATD group (p = 1.0).

CONCLUSION

While it is preferable to render patients euthyroid prior to thyroidectomy for hyperthyroidism, results of this study suggest that when patients cannot tolerate ATDs, it is possible to perform thyroidectomy without increased risk of thyroid storm or intra- and postoperative complications.

Prediction of post-idroidectomy hypocalcemia through rapid PTH determination

INTRODUCTION

Hypocalcemia is the most frequent complication after thyroidectomy. The aim of this work is to identify biochemical risk factors of hypocalcemia using quick perioperative (pre and post-thyroidectomy) intact parathyroid hormone (PTHi) and postoperative calcemias.

METHODS

In a consecutive series of 310 total thyroidectomies, samples of quick PTHi at the anaesthetic induction and 10 minutes after surgery, together with serum calcemias every 12 hours were obtained. The sensitivity, specificity, positive and negative predictive value are analyzed and related to hypocalcemia. A control group of hemithyroidectomies is also analyzed to compare the effects of surgery on PTH secretion.

RESULTS

Of the 310 patients, 202 (65.1%) remained normocalcemic and asymptomatic (group A), 108 (34.9%) presented hypocalcemia (Group B), requiring oral calcium (79 symptomatic). After analysis of several cut-off points, combining a PTHr drop gradient of 60% or calcemia inferior to 7.4 mg/dl at 24 hours, a sensitivity of 100% is achieved without leaving false negatives. Compared to the control group, there is a significant difference with respect to the post-operative calcemias and PTHr, p < 0.001.

CONCLUSIONS

Total thyroidectomy affects parathyroid function with evident decrease in rPTH and risk of hypocalcemia. The combination of PTHr decrease of 60% or less than 7.4 mg/dl calcemia at 24 hours gives a 100% sensitivity for predicting patients at risk of hypocalcemia.

Identifying early postoperative serum parathyroid hormone levels as predictors of hypocalcaemia after total thyroidectomy: A prospective non-randomized study

OBJECTIVE

There is no clear cut-off value of serum parathyroid hormone (PTH) or calcium in which patients are at risk for hypocalcemia after total thyroidectomy. We evaluated the usefulness of serum calcium and PTH concentration measurements after total thyroidectomy in predicting late-occurring hypocalcemia.

DESIGN

A prospective, single-center, non-randomized longitudinal cohort study of 143 patients undergoing thyroidectomy between August 2019 and December 2019 with serum calcium and PTH levels sampled 1 h after surgery and on the first and fifth postoperative day. Hypocalcemia was defined as serum calcium levels < 2.14 mmol/L regardless of clinical symptoms. Normal PTH range was 1.6-6.9 pmol/L.

MEASUREMENTS

The primary outcome measure was presence of hypocalcemia on the first and fifth postoperative day, analyzed by a logistic regression model. The PTH cut-off value for prediction of hypocalcemia was identified using a ROC curve comparing all three time points using the Youden J index.

RESULTS

Out of 143 patients, 52 (36.4%) had hypocalcemia on the fifth postoperative day. Advanced age, concomitant neck dissection and serum PTH levels < 2.9 pmol/L 1 h after surgery and on the first postoperative surgery day were associated with a high risk of hypocalcemia on the first and fifth postoperative day and need for higher doses of calcium supplements (P < 0.0001, AUC 0.748, 95% CI 0.669-0.817, with 76.92% sensitivity and 71.43% specificity).

CONCLUSION

Serum PTH level measured immediately postoperatively and on the first postoperative day is a reliable predictor of postoperative hypocalcemia with important clinical implications.

Outpatient thyroidectomy in the pediatric population

Preoperative optimization and patient education have allowed for the transition of thyroid surgery to the outpatient setting over the last few decades. Performing these operations in the outpatient setting has proven to be cost-effective and safe in the adult population. The purpose of this study is to evaluate the safety and efficacy of outpatient thyroid surgery in the pediatric population. A retrospective review from December 2015 to February 2019 of patients under the age of 18 years of age undergoing thyroidectomy performed by two endocrine surgeons at a large academic was performed. There were 55 consecutive operations performed in 51 patients for thyroid pathology, two were excluded as they were inpatient procedures. Cases were reviewed for complications, unplanned same-day admission, 30-day admission, unplanned reoperation, and death. Mean age was 15 ± 0.3 years (range 9-18 years), 79% of the patients were female. Operations were performed for Graves' disease (n = 29), thyroid cancer (n = 9), thyroid nodule (n = 6), multinodular goiter (n = 4), Hashimoto's disease (n = 3), and toxic adenoma (n = 2). Operations performed included: total thyroidectomy (n = 36), thyroid lobectomy (n = 13), total thyroidectomy with lymph node dissection (n = 2), and lateral neck dissection (n = 2). All patients were discharged home within 6 h after completion of the operation. Five (9.4%) patients had transient hypoparathyroidism, with parathyroid hormone levels <10 pg/mL immediately postoperatively. One patient (1.9%) developed a postoperative hematoma on postoperative day six and required reoperation and readmission. Two patients (3.8%) had permanent hypoparathyroidism and one had transient hoarseness (1.9%). There were otherwise no readmissions or ED visits. In conclusion, outpatient thyroid surgery is safe and effective for pediatric patients.

Severe Hypocalcemia After Thyroidectomy: An Analysis of 7366 Patients

OBJECTIVE

The aim of the study was to determine severe hypocalcemia rate following thyroidectomy and factors associated with its occurrence.

BACKGROUND

Hypocalcemia is the most common complication after thyroidectomy. Severe post-thyroidectomy hypocalcemia can be life-threatening; data on this specific complication are scarce.

METHODS

Patients who underwent thyroidectomy in the American College of Surgeons-National Surgical Quality Improvement Program thyroidectomy-targeted database (2016-2017) were abstracted. A severe hypocalcemic event was defined as hypocalcemia requiring intravenous calcium, emergent clinic/hospital visit, or a readmission for hypocalcemia. Multivariable regression was used to identify factors independently associated with occurrence of severe hypocalcemia.

RESULTS

Severe hypocalcemia occurred in 5.8% (n = 428) of 7366 thyroidectomy patients, with 83.2% necessitating intravenous calcium treatment. Rate of severe hypocalcemia varied by diagnosis and procedure (0.5% for subtotal thyroidectomy to 12.5% for thyroidectomy involving neck dissections). Overall, 38.3% of severe hypocalcemic events occurred after discharge; in this subset, 59.1% experienced severe hypocalcemia despite being discharged with calcium and vitamin D. Severe hypocalcemia patients had higher rates of recurrent laryngeal nerve injury (13.4% vs 6.6%), unplanned reoperations (4.4% vs 1.3%), and longer hospital stay (30.4% vs 6.2% ≥3 days (all P < 0.01). After multivariate adjustment, severe hypocalcemia was associated with multiple factors including Graves disease [odds ratio (OR) = 2.06], lateral neck dissections (OR: 3.10), and unexpected reoperations (OR = 3.55); all P values less than 0.01.

CONCLUSIONS

Severe hypocalcemia and suboptimal hypocalcemia management after thyroidectomy are common. Patients who experienced severe hypocalcemia had higher rates of nerve injury and unexpected reoperations, indicating surgical complexity and provider inexperience. More biochemical surveillance particularly a parathyroid hormone-based protocol, fine-tuned supplementation, and selective referral could reduce occurrence of this morbid complication.

Preoperative vitamin D deficiency is a risk factor for postoperative hypocalcemia in patients undergoing total thyroidectomy: retrospective cohort study

BACKGROUND

The relationship between preoperative vitamin D deficiency and postoperative hypocalcemia in cases of total thyroidectomy (TT) is a matter of controversy and may vary according to geographical scenarios and populations.

OBJECTIVE

The objective here was to evaluate whether preoperative vitamin D deficiency was associated with postoperative symptomatic hypocalcemia in a population in South America.

DESIGN AND SETTING

Retrospective cohort study on data from all patients undergoing total thyroidectomy, with or without central compartment lymph node dissection, from January 2014 to December 2017, at the A. C. Camargo Cancer Center.

METHODS

Patients with benign thyroid disease (Graves' disease, multinodular goiter or hyperthyroidism) or thyroid cancer who underwent primary total thyroidectomy with or without central compartment lymph node dissection were included. The exclusion criteria were simultaneous parathyroidectomy and conditions that could affect serum calcium levels. The data collected included patient demographics, thyroid pathology, extent of the surgical procedure and complications. Information on preoperative and postoperative calcium, parathyroid hormone (PTH) and vitamin D levels were retrieved from the medical records.

RESULTS

1,347 patients were assessed and postoperative hypocalcemia was diagnosed in 284 patients (21%). The vitamin D levels were considered deficient in 243 patients (18%). Postoperative hypocalcemia was diagnosed in 357 patients (31.5%). Multivariate analysis showed that central compartment dissection and preoperative total calcium and deficient vitamin D levels were significant risk factors for postoperative hypocalcemia.

CONCLUSION

Deficient preoperative vitamin D levels were a significant risk factor for postoperative hypocalcemia. Preoperative oral supplementation should be considered, to minimize this risk.

Post-thyroidectomy Hypocalcemia in Patients With History of Bariatric Operations: Current Evidence and Management Options

BACKGROUND/AIM

Both bariatric and thyroid surgeries promote calcium and vitamin D deficiency. The correlation, however, of hypocalcemia after thyroidectomy in patients with previous bariatric surgery has been poorly described. This review aimed to investigate the relationship between history of bariatric operations and post-thyroidectomy hypocalcemia, as well as suggested management options.

MATERIALS AND METHODS

MEDLINE and Cochrane databases were searched for relevant publications regarding post-thyroidectomy hypocalcemia in patients with previous bariatric surgery.

RESULTS

A total of 17 publications reporting on 126 patients met the inclusion criteria. These included 13 publications about Roux-en-Y gastric bypass (RYGB), 2 regarding biliopancreatic diversion (BPD), 1 about sleeve gastrectomy (SG) and 1 compared three bariatric procedures: SG, RYGB, laparoscopic adjustable gastric band (LAGB). Post-thyroidectomy hypocalcemia was found to be more prevalent in patients with previous RYGB and BPD, but not in previous LAGB and SG.

CONCLUSION

Patients with previous bariatric surgery are at high risk of post-thyroidectomy hypocalcemia that sometimes leads to higher length of hospital stay and demands more invasive solutions. There is a need, however, for additional studies and further investigation in order to reach more conclusive results.

Meta-analysis of routine calcium/vitamin D3 supplementation versus serum calcium level-based strategy to prevent postoperative hypocalcaemia after thyroidectomy

BACKGROUND

The aim was to assess the effectiveness of routine administration of calcium +/- vitamin D3 compared with a serum calcium level-based strategy to prevent symptomatic hypocalcaemia after thyroidectomy.

METHODS

RCTs comparing routine supplementation of calcium +/- vitamin D3 with treatment based on serum calcium levels measured after total thyroidectomy, published between 1980 and 2017, were identified in MEDLINE, Embase, LILACS and Google Scholar databases. Risk of bias was evaluated using the Cochrane Collaboration tool. Risk differences were calculated by random-effects meta-analysis. Meta-regression and cumulative meta-analysis were used to explore the best therapeutic approach.

RESULTS

Fifteen studies with 3037 patients were included, and seven treatment comparisons were made. Routine supplementation with calcium + vitamin D3 offered a lower risk of symptomatic (risk difference (RD) -0·25, 95 per cent c.i. -0·32 to -0·18) and biochemical (RD -0·24, -0·31 to -0·17) hypocalcaemia than treatment based on measurement of calcium levels. The number needed to treat was 4 (95 per cent c.i. 3 to 6) for symptomatic hypocalcaemia. No publication bias was found; although heterogeneity was high for some comparisons, sensitivity analysis did not change the main results.

CONCLUSION

Routine postoperative administration of calcium + vitamin D3 is effective in decreasing the rate of symptomatic and biochemical hypocalcaemia.

Calcium, vitamin D or recombinant parathyroid hormone for managing post-thyroidectomy hypoparathyroidism

BACKGROUND

Post-surgical hypoparathyroidism is a common complication after thyroid surgery. The incidence is likely to increase given the rising trend in the annual number of thyroid operations being performed. Measures to prevent post-thyroidectomy hypoparathyroidism including different surgical techniques and prophylactic calcium and vitamin D supplements have been extensively studied. The management of post-thyroidectomy hypoparathyroidism however has not been extensively evaluated. Routine use of calcium and vitamin D supplements in the postoperative period may reduce the risk of symptoms, temporary hypocalcaemia and hospital stay. However, this may lead to overtreatment and has no effect on long-term hypoparathyroidism. Current recommendations on the management of post-thyroidectomy hypoparathyroidism is based on low-quality evidence. Existing guidelines do not often distinguish between surgical and non-surgical hypoparathyroidism, and transient and long-term disease.The aim of this systematic review was to summarise evidence on the use of calcium, vitamin D and recombinant parathyroid hormone in the management of post-thyroidectomy hypoparathyroidism. In addition, we aimed to highlight deficiencies in the current literature and stimulate further work in this field.

OBJECTIVES

The objective of this systematic review was to assess the effects of calcium, vitamin D and recombinant parathyroid hormone in managing post-thyroidectomy hypoparathyroidism.

SEARCH METHODS

We searched CENTRAL, MEDLINE, PubMed, Embase as well as ICTRP Search Portal and ClinicalTrials.gov. The date of the last search for all databases was 17 December 2018 (except Embase, which was last searched on 21 December 2017). No language restrictions were applied.

SELECTION CRITERIA

We planned to include randomised control trials (RCTs) or controlled clinical trials (CCTs) examining the effects of calcium, vitamin D or recombinant parathyroid hormone in people with temporary and long-term post-thyroidectomy hypoparathyroidism.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts and full texts for relevance.

MAIN RESULTS

Database searches yielded a total of 1751 records. We retrieved potentially relevant full texts and excluded articles on the following basis: not a RCT or CCT; intervention, comparator or both did not match prespecified criteria; non-surgical causes of hypoparathyroidism, and studies on prevention. None of the articles was eligible for inclusion in the systematic review.

AUTHORS' CONCLUSIONS

This systematic review highlights a gap in the current literature and the lack of high-quality evidence in the management of post-thyroidectomy temporary and long-term hypoparathyroidism. Further research focusing on clinically relevant outcomes is needed to examine the effects of current treatments in the management of temporary and long-term post-thyroidectomy hypocalcaemia.

Same day discharge after thyroidectomy is safe and effective

Historically, thyroidectomies have been performed as inpatient operations due to concerns of postoperative bleeding and symptomatic hypocalcemia. We aim to demonstrate that outpatient thyroidectomy can be performed safely.

METHODS

This report outlines a 7-year retrospective analysis (2009-2016) of outpatient vs inpatient thyroidectomies, with outcomes including hematoma, blood loss, recurrent laryngeal nerve injury, symptomatic hypocalcemia, and postoperative emergency room (ER) visits.

RESULTS

A total of 1460 thyroidectomies were performed: 1272 (87%) outpatient and 188 (13%) inpatient. Five outpatients: 4 total thyroidectomies (TT), 1 TT with a central lymph node dissection (CLND), and 1 partial thyroidectomy (PT) developed postoperative hematomas (0.34%) at post-discharge hour 3, 9, 10, 13, and 42. Average time to discharge was 2 hours and 37 minutes. Hematomas were evacuated successfully in the operating room under local anesthesia with a 2-day average hospital stay. There were no differences between TT, thyroid lobectomy (TL), and PT procedures for postoperative hematoma (p=0.17). Outpatient compared to inpatient thyroidectomy was more likely to have been performed in patients with lower American Society of Anesthesia scores (2.3 vs 2.9, p<0.0001), less mean blood loss (74 vs 227 ml, p<0.0001), lesser age (52 vs 56 years, p=0.0012), less extensive dissection (p<0.0001), and fewer RLN injuries (2.4% vs 8.5%, p<0.0001). There was no difference between outpatient and inpatient symptomatic hypocalcemia (6.3% vs 9.6%, p=0.09), 30-day postoperative ER visits (8.8% vs 9.6%, p=0.73), and postoperative hematoma (0.39% vs 0%, p=0.39). There was one inpatient mortality from stroke.

CONCLUSION

Postoperative hematomas can be managed safely without life-threatening complications suggesting outpatient thyroidectomy can be performed safely by an experienced surgeon, and adverse sequelae dealt with in a safe and effective manner.

Early corrected serum calcium value can predict definitive calcium serum level after total thyroidectomy in asymptomatic patients

INTRODUCTION

Hypocalcemia is the most common complication of thyroidectomy, requiring supplementation as well as prolonged hospitalization. Our study's objective was to determine a corrected calcium (CCa) level on day 1 after thyroidectomy predictive of no calcium and vitamin supplementation.

MATERIALS AND METHODS

A single-center prospective study conducted between January 2012 and July 2015 in 396 patients, consisting of 331 cases of total thyroidectomy, with seven completion surgeries. The data collected were age, sex, type of thyroid surgery, etiology, anatomical pathological analysis, and the need for calcium and vitamin supplementation therapy as well as its duration. CCa levels were analyzed 20 and 30 h after surgery then on days 2 and 3. To determine a cut-off value for CCa, a ROC curve analysis was performed. The population was described in terms of numbers and associated percentages for categorical variables, and mean.

RESULTS

Mean CCa on 20 h after surgery was 2.09 mmol/L (p < 0.001) and 30 h was 2.06 mmol/L p = 0.02. CCa of less than 2.13 mmol/L was predictive of calcium and vitamin supplementation with 56% sensitivity and 97% specificity. On the evening of day 1, the cut-off value for CCa was 2.06 mmol/L with 67% sensitivity and 65% specificity.

CONCLUSION

This prospective study confirms that CCa on the first morning after surgery is reliable when it is more than 2.13 mmol/L. In total, analyzing CCa on day 1 after total thyroidectomy allows the discharge of 70% of patients on the first day after surgery, with no risk of hypocalcemia.

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

Background

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

Methods

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

Results

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

Conclusions

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

•

Predictive factors of postoperative hypocalcemia.

•

Retrospective study of 345 patients.

•

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

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

BACKGROUND

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

OBJECTIVE

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Diagnosis and treatment of hypoparathyroidism: a position statement from the Brazilian Society of Endocrinology and Metabolism

Objective To present an update on the diagnosis and treatment of hypoparathyroidism based on the most recent scientific evidence. Materials and methods The Department of Bone and Mineral Metabolism of the Sociedade Brasileira de Endocrinologia e Metabologia (SBEM; Brazilian Society of Endocrinology and Metabolism) was invited to prepare a document following the rules set by the Guidelines Program of the Associação Médica Brasileira (AMB; Brazilian Medical Association). Relevant papers were retrieved from the databases MEDLINE/PubMed, LILACS, and SciELO, and the evidence derived from each article was classified into recommendation levels according to scientific strength and study type. Conclusion An update on the recent scientific literature addressing hypoparathyroidism is presented to serve as a basis for the diagnosis and treatment of this condition in Brazil.

The role and timing of parathyroid hormone determination after total thyroidectomy

Postoperative hypocalcemia is a common complication of total thyroidectomy resulting from manipulation, resection, or devascularization of the parathyroid glands. Parathyroid hormone (PTH) levels assessed in the perioperative period have been used to predict development of hypocalcemia. Articles examining the role of PTH measurement in the perioperative period following total or completion thyroidectomy are reviewed. Focus is placed on the timing of PTH measurement and the ability to predict which patients will develop hypocalcemia requiring supplementation. Postoperative PTH determination is highly accurate in predicting the development of hypocalcemia. Studies have examined PTH levels drawn at differing time points, ranging from intraoperatively until postoperative day 1 (POD1) with similar accuracy. This data is used to guide postoperative selective calcium and calcitriol supplementation in patients at highest risk for hypocalcemia. When evaluated within the first 4 hours postoperatively, predictive accuracy is maintained but can allow for earlier discharge for those patients at lower risk. Alternatively, some authors argue for routine supplementation, which can reduce the rate of postoperative hypocalcemia but increases the rate of unnecessary supplementation and potential risks associated with hypercalcemia. PTH determination at four hours after total thyroidectomy is an accurate predictor of hypocalcemia and can guide selective calcium supplementation for those at high risk, as well as facilitate a safe earlier hospital discharge for those at low risk of developing postoperative hypocalcemia.

Impact of autofluorescence-based identification of parathyroids during total thyroidectomy on postoperative hypocalcemia: a before and after controlled study

BACKGROUND

The clinical impact of intraoperative autofluorescence-based identification of parathyroids using a near-infrared camera remains unknown.

METHODS

In a before and after controlled study, we compared all patients who underwent total thyroidectomy by the same surgeon during Period 1 (January 2015 to January 2016) without near-infrared (near-infrared- group) and those operated on during Period 2 (February 2016 to September 2016) using a near-infrared camera (near-infrared+ group). In parallel, we also compared all patients who underwent surgery without near-infrared during those same periods by another surgeon in the same unit (control groups). Main outcomes included postoperative hypocalcemia, parathyroid identification, autotransplantation, and inadvertent resection.

RESULTS

The near-infrared+ group displayed significantly lower postoperative hypocalcemia rates (5.2%) than the near-infrared- group (20.9%; P < .001). Compared with the near-infrared- patients, the near-infrared+ group exhibited an increased mean number of identified parathyroids and reduced parathyroid autotransplantation rates, although no difference was observed in inadvertent resection rates. Parathyroids were identified via near-infrared before they were visualized by the surgeon in 68% patients. In the control groups, parathyroid identification improved significantly from Period 1 to Period 2, although autotransplantation, inadvertent resection and postoperative hypocalcemia rates did not differ.

CONCLUSION

Near-infrared use during total thyroidectomy significantly reduced postoperative hypocalcemia, improved parathyroid identification and reduced their autotransplantation rate.

[Intraoperative parathyroid hormone measurement is the best predictor of postoperative symptomatic hypocalcemia]

BACKGROUND

The goal of this study is to evaluate risk factors for transient postoperative hypocalcemia (HC) and to define cutoff values for perioperative parathyroid hormone (PTH) and calcium parameters (Ca) to reduce the morbidity of symptomatic HC.

MATERIALS AND METHODS

At our tertiary referral hospital (Luzerner Kantonsspital, Switzerland), a total of 353 patients underwent total thyroidectomy between 2006 and 2013 and were analyzed retrospectively in terms of HC risk. The serum values of calcium and PTH were measured at strictly defined time intervals, and patients' symptoms and the necessity of treatments were determined from patients' charts.

RESULTS

The prevalence of transient postoperative HC was 43%; however, only 10% of patients were symptomatic. Significant risk factors for serum and symptomatic HC were calcium values (pre-, intra-, 4 h and 1 d postoperative), PTH values (intraoperative, 4 h and 1 d postoperative), and PTH decline. Interestingly, preoperative PTH values, patient age, weight of the thyroid gland, diagnosis, and sex were not significant risk factors. In the ROC analysis ('receiver operating characteristics'), calcium measurement 4 h postoperatively showed the best predictive ability for detecting serum HC, whereas intraoperative PTH measurements were predictive for symptomatic HC.

CONCLUSION

Calcium and PTH values as well as PTH decline are significant risk factors for postoperative HC. Preoperatively, only calcium measurement is prognostically significant. Intraoperative PTH measurement is the most reasonable and sensitive factor for early recognition of temporary postoperative HC in the clinical setting.

Is Decline Rate of Intact Parathyroid Hormone Level a Reliable Criterion for Early Discharge of Patients after Total Thyroidectomy?

INTRODUCTION

Parathyroid dysfunction leading to symptomatic hypocalcemia is not uncommon following a total thyroidectomy and is often associated with significant patient morbidity and a prolonged hospital stay. The current study aimed at evaluating the comparative predictive role of serum calcium and intact parathyroid hormone (iPTH) for post-thyroidectomy hypocalcemia.

MATERIALS AND METHODS

This prospective study was performed in 83 consecutive patients undergoing total thyroidectomy. Laboratory data such as serum calcium, vitamin D level, serum iPTH and serum phosphorus levels before surgery, postoperative calcium, and PTH levels measured after 1 and 6 hours and on the first postoperative day (1POD) were recorded.

RESULTS

Among the 83 patients, the mean (SD) age was 45.87 (12.57) years (range, 21-72 years); 70 (84.3%) patients were female. Final pathology was benign for 47 (56.6%) patients and malignant for 36 (43.4%) patients. In total, lymph node dissections were performed in 19 subjects (22.9%). On histological examination of the specimens, the parathyroid gland was found to have been removed inadvertently in 13 (15.7%) cases. In total, 35 (40.9%) patients developed hypocalcemia after thyroidectomy; receiver operating characteristic (ROC) analysis showed that a cut-off value of 15.39 pg/ml for iPTH, with a decline rate of 73% 1 hour after thyroidectomy is a significant predictor of hypocalcemia (area under the curve [AUC], 0.878; 95% confidence interval [CI], 0.79-0.96, P<0.0001) compared with calcium <8 mg/dl (2 mmol/L) with AUC=0.639; 95% CI, 0.51-0.76); P=0.067).

CONCLUSION

The current study showed that the decline rate in iPTH is a more reliable factor for hypocalcemia after total thyroidectomy than serum calcium. Patients with a decline rate <73% in iPTH could be discharged at 1POD without supplementation.

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

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

Early intact PTH (iPTH) is an early predictor of postoperative hypocalcemia for a safer and earlier hospital discharge: an analysis on 260 total thyroidectomies

BACKGROUND

Hypocalcemia is the most frequent complication after thyroidectomy. Serum calcium levels are reliable only 48-72 hours postoperatively. Early intact PTH (iPTH) has been proposed as early predictor of postoperative hypocalcemia. Our aim is to assess the ability of iPTH in predicting postoperative hypocalcemia.

METHODS

Two hundred and sixty patients underwent thyroidectomy with postoperative iPTH evaluation. The iPTH samplings were early performed after thyroidectomy. The calcium levels were dosed postoperatively. Age, sex, clinical diagnosis, obesity, comorbidities, previous neck surgery, preoperative therapy, type of surgery, dissectors used, lymphadenectomy, post-operative complications, reoperation and histological diagnosis were considered. The primary end-point was the postoperative hospital stay. The secondary end-points were serum calcium and iPTH. Three iPTH cut-offs were tested to assess which was the best value (10.0, 15.0, and 20.0 pg/mL).

RESULTS

The iPTH cut-off value of 10.0 pg/mL was the most accurate and specific for hypocalcemia. Comparing the iPTH value with the different values of calcium respectively 24 and 48 hours after surgery, a statistically stronger association with the serum calcium levels 48 hours postoperatively has been shown. iPTH ≥10 pg/mL 3-6 hours after surgery was strongly correlated to early discharge.

CONCLUSIONS

The correlation of iPTH with hypocalcemia is significant since a few hours after surgery and the value of iPTH ≥10 pg/mL is able to select those patients for a safe and early discharge. The use of the iPTH might avoid unnecessary extensions of hospitalization.

Outcome of hypocalcaemia after thyroidectomy treated only in symptomatic patients

BACKGROUND

Calcium supplementation has been proposed after bilateral thyroid surgery, either to all patients or to those with biochemical hypocalcaemia. It has also been suggested that supplementation aids parathyroid recovery and prevents permanent hypoparathyroidism. This single-centre study investigated the feasibility of a restrictive management of post-thyroidectomy hypocalcaemia.

METHODS

Serum calcium was checked before surgery, on postoperative day 1 (POD) 1, at a follow-up visit 6-8 weeks after surgery and after a minimum of 12 months in all patients. Regardless of serum calcium levels, patients with symptoms of hypocalcaemia were prescribed oral calcium supplementation (0·5-1·0 g twice daily) and asymptomatic patients were not. Asymptomatic patients were informed about hypocalcaemic symptoms and instructed to contact the surgical ward should symptoms appear.

RESULTS

Some 640 patients underwent bilateral thyroid surgery without previous or intentional simultaneous parathyroidectomy. A subnormal serum calcium level (below 2·15 mmol/l) was observed in 412 patients (64·4 per cent) on POD 1. By comparison, only 63 patients (9·8 per cent) experienced symptoms of hypocalcaemia in the postoperative period, all but one with a corresponding biochemical hypocalcaemia on POD 1. Calcium levels in all patients with asymptomatic postoperative hypocalcaemia recovered to normal without supplementation. Serum calcium was also normalized during follow-up in all symptomatic patients, except 22 (3·4 per cent) who became permanently hypoparathyroid. No patient without early hypocalcaemic symptoms developed permanent hypoparathyroidism.

CONCLUSION

The proposed restrictive management of postoperative hypocalcaemia after bilateral thyroid surgery avoids unnecessary supplementation for most patients.

Single measurement of intact parathyroid hormone after thyroidectomy can predict transient and permanent hypoparathyroidism: a prospective study

OBJECTIVE

Immediate postoperative hypocalcemia is the most common complication of bilateral thyroidectomy. Although hypocalcemia is usually transient, it can be fatal. This study aimed to find a predictor of immediate postoperative hypocalcemia by using intact parathyroid hormone (PTH) level at 4 hours after thyroidectomy (iPTH4hr) compared with the decline in the percentage of intact PTH (%iPTH). We also followed the subjects for evaluation of permanent hypoparathyroidism.

METHODS

This was a prospective study of 65 patients (86.2% female, mean age: 43±15 years) who planned to undergo total or subtotal thyroidectomy. Preoperative and iPTH4hr were measured.

RESULTS

Thirty-nine patients (60%) were diagnosed with papillary thyroid carcinoma, while the rest were multinodular goiter (21.5%) and Graves' disease (7.7%). Significant immediate hypocalcemia was observed in 25 (38.5%) patients. Both iPTH4hr <12.5 pg/mL and %iPTH decline >72% could accurately predict significant immediate hypocalcemia. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for iPTH4hr were 92%, 87.5%, 82.1%, and 94.6%, respectively. The %iPTH decline was equal in accuracy, with sensitivity, specificity, PPV, and NPV of 84%, 90%, 84%, and 90%, respectively. At 6 months after surgery, 19 patients (29.2%) displayed permanent hypoparathyroidism. The iPTH4hr <12.5 pg/mL and %iPTH decline >72% could also predict permanent hypoparathyroidism, with sensitivity, specificity, PPV, and NPV of 100%, 80.4%, 67.9%, and 100%, and 94.7%, 84.8%, 72%, and 97.5%, respectively.

CONCLUSIONS

Only a single measurement of iPTH4hr could be helpful in identifying patients at risk of significant immediate hypocalcemia in need prompt treatment, and subsequently facilitating early discharge of patients. Also, this parameter can precisely predict permanent hypoparathyroidism.