Perioperative Parathyroid Hormone Research Articles

A new approach for perioperative parathyroid hormone (PTH) measurement to establish cure in patients with primary hyperparathyroidism.

In this study, we analyse the possibility to omit pre-incision PTH measurement since we routinely measure it at the time of pre-surgery ambulatory admission. A total of 435 patients were enrolled. All patients with pHPT included underwent pre-surgical PTH level assessment as part of the pre-admission preparation to surgery. Intraoperative PTH was routinely assessed after induction of the anaesthesia (pre-incision PTH) and 15min after resection of the enlarged gland(s) (post-excision PTH). Moreover, calcium and PTH levels were routinely assessed on the first postoperative day. Cure was defined as an intraoperative drop of > 50% or into normal range on first post-operative day. The median value of the preoperative and pre-incision PTH were both 127 pg/ml (p = ns). Thirty-two patients (7.3%) exhibited a not appropriate drop of post-excision PTH level. Nevertheless, nineteen of them (59.3%) showed a satisfying PTH drop on 1st POD. Ten patients (2.3%) experienced a persistent disease with six achieving cure through reoperation. Additionally, three patients (0.6%) showed normalization of calcium and PTH values during the follow-up. Three patients, apparently deemed cured after an adequate PTH-drop on the day of surgery, showed persistence. Cure rate at primary surgery was 98.4%. Accuracy of our simplified protocol is 99.3%. Pre-incision PTH is not superior to preoperative PTH blood test and can be omitted without compromising the sensitivity of cure prediction. One blood sample 15min after resection, along with the postoperative PTH value on the day after surgery, is sufficient to predict the surgical outcome bearing the cost of a very low reoperation rate.

Postoperative parathyroid hormone (PTH) is equivalent to perioperative PTH drop in predicting postsurgical hypoparathyroidism.

Postoperative surgical hypoparathyroidism (PoSH) following thyroid surgery is an established complication. Several predictive factors have been identified including perioperative parathyroid hormone (PTH) levels. The aim of the study is to compare the drop in perioperative PTH to postoperative day 1 PTH in predicting hypocalcaemia and hypoparathyroidism. Records of consecutive patients who had either total or completion thyroidectomy with or without central neck dissection in a 3-year period in a single thyroid surgery unit were accessed to retrieve data on demographics, pathology, surgery, perioperative biochemistry and management. Of 295 included patients, there were 227 (76.9%) females. Forty-five (15.3%) had completion thyroidectomy, and the rest had total thyroidectomy. Seventy-eight (26.4%) had concomitant central neck dissection. Sixty-four (21.7%) had hypocalcaemia on the day after surgery. Hypoparathyroidism persisted in 10.5% of patients at 6 months. Both day 1 PTH and a drop in PTH predicted day 1 hypocalcaemia (p < 0.001) and 6-month hypoparathyroidism (p < 0.001). The area under the receiver operating characteristic (ROC) curves for day 1 PTH and drop in PTH for the prediction of day 1 hypocalcaemia (0.729 vs 0.726, respectively) and for 6-month hypoparathyroidism (0.964 vs 0.958, respectively) were similar, albeit slightly better for day 1 PTH. Day 1 PTH is equivalent to (if not better than) drop in PTH in predicting short- and long-term PoSH. Preoperative PTH measurements may not be needed in the detection and/or management of PoSH after thyroid surgery.

Do peri-operative parathyroid hormone (PTH) analogues improve bone density and decrease mechanical complications in spinal deformity correction?—a minimum 2-year radiological study measuring Hounsfield units

ObjectiveTo delineate whether use of a PTH analogue in the 1-year peri-operative period improves lumbar bone density.MethodsA prospectively collected data registry of 254 patients who underwent CMIS correction of ASD (Cobb angle > 20 or SVA > 50 mm or (PI-LL) > 10) from Jan 2011 to Jan 2020 was analysed. Patients who were placed on PTH analogues for one year in conjunction with surgery were included in the study. Ultimately, 41 patients who had pre- and two-year post-operative CT scans for review were included in this study. Hounsfield units were measured off of the L1–L3 levels for all patients before and after surgery on pre-op and post-op CT scans.ResultThe mean age of patients in this study was 70 (52–84, SD 7). Mean follow-up was 66 (24–132, SD 33) months. Twenty-three patients met criteria for severe deformity (Cobb angle > 50 degrees or SVA > 95 mm or PI/LL mismatch > 20 or PT > 30). Based off 2-year post-op CT scan, there were significant improvements in L1 Hounsfield units when comparing pre-op values (96; SD 55) to post-op values (185 SD 102); p. < 0.05. There was no screw loosening or screw pull out. There were 2 patients with PJF (4.8%). Both these patients had not completed their PTH treatment: one only took PTH for 3 months (PJF at 2-year post-op) and the other one took it only for 1 month (PJF at 1-year post-op). No increase in bone density was noted (based off of Hounsfield units) in five patients (12%) despite completion of their PTH therapy. Only one patient experienced nausea from PTH therapy. There were no other PTH related adverse events.ConclusionThe incidence of PTH analogues failing to increase bone density in our series was low at 12%. This study shows that PTH analogues may be a powerful adjunct for increasing bone density and may help to mitigate the risk of mechanical complications in patients undergoing deformity correction with minimally invasive techniques. Future comparative studies are warranted to confirm these latter findings and to potentially protocolize the ideal peri-operative bone health optimization strategy.

Is perioperative drop in PTH better than postoperative PTH in predicting hypocalcaemia after thyroid surgery?

Abstract Introduction Postoperative surgical hypoparathyroidism (PoSH) following thyroid surgery is well known complication. Several predictive factors have been identified including perioperative parathyroid hormone (PTH) levels. The aim of the study is to determine how a drop in perioperative parathyroid hormone (PTH) compares to postoperative day one PTH in predicting hypocalcaemia. Methods Medical records of consecutive patients who had either total or completion thyroidectomy with or without central neck dissection between January 2016 and December 2018 in a single thyroid surgery unit were accessed to retrieve data on demographics, pathology, surgery, perioperative biochemistry and management. Results Of 295 included patients, there were 227 (76.9%) females. Forty-five (15.3%) had completion thyroidectomy, while the rest had total thyroidectomy. Seventy-eight (26.4%) had concomitant central neck dissection. 64 (21.7%) had day 1 hypocalcaemia and this was persistent at six months in 31 patients (10.5%). Both day one PTH and drop in PTH predicted day one hypocalcaemia (P&amp;lt;0.001) and 6-month hypoparathyroidism (p&amp;lt;0.001). The area under ROC curves for day one PTH and drop in PTH for day one hypocalcaemia (0.729 vs 0.726 respectively) and for 6-month hypoparathyroidism (0.964 vs 0.958 respectively) were similar; albeit slightly better for day 1 PTH. Conclusion Day 1 PTH is equivalent to (if not better than) drop in PTH in predicting short and long term PoSH. Preoperative PTH measurements are therefore not needed in detection and/or management of PoSH after thyroid surgery.

Prediction of Post Total Thyroidectomy Hypocalcaemia using Perioperative Parathyroid Hormone

Thyroidectomy is one of the most common operations performed worldwide by various surgeons whether general or endocrine surgeons. The rate of complications following thyroidectomy has been progressively decreasing yet it still carries significant morbidity if preoperative preparation and patient as well as procedure selection were not optimized. The aim of this study is to evaluate the reliability of perioperative parathyroid hormone measurement to predict post-total thyroidectomy hypocalcaemia.Our study was prospective non-randomized study done from November 2018 till September 2019 in Benha university hospital, general surgery department, Benha, Egypt. The study included 50 patients having thyroid disease for whom total thyroidectomy was indicated. From the study serum calcium concentrations have been the basis of identification of post-operative hypocalcaemia however this has been replaced by PTH levels being more sensitive and specific to the early prediction of hypocalcaemia. In the study a drop in postoperative PTH levels by more than 62% compared to preoperative level giving 75% Sensitivity, 84.21% Specificity, PPV 60% and NPV 91.43%. a drop in postoperative PTH levels by more than 62% may serve as a sensitive and specific indicator of hypocalcemia with high overall accuracy and this will help in selecting patients for early discharge after total thyroidectomy.

18F-Fluorocholine PET and Multiphase CT Integrated in Dual Modality PET/4D-CT for Preoperative Evaluation of Primary Hyperparathyroidism.

The present retrospective study evaluates the diagnostic value of integrated 18F-Fluorocholine positron emission tomography/four-dimensional contrast-enhanced computed tomography (18F-FCH PET/4D-CT) as second-line imaging in preoperative work-up of primary hyperparathyroidism (pHPT), and compares 18F-FCH PET with 4D-CT. Patients with pHPT and negative/discordant first-line imaging addressed for integrated 18F-FCH PET/4D-CT were retrospectively selected. Sensitivity and detection rate (DR%) of 18F-FCH PET/CT, 4D-CT, and PET/4D-CT were calculated according to the per patient and per lesion analyses, and afterwards compared. Histology associated with a decrease more than 50% of perioperative parathyroid hormone (PTH) blood level was used as a gold standard. Persistent high serum PTH and calcium levels during a 6-month follow-up was considered as presence of pHPT in both operated and non-operated patients. 50 patients (55 glands) were included. 44/50 patients (88%) were surgically treated. On a per patient analysis, sensitivity was 93%, 80%, and 95%, and DR% was 82%, 68%, and 84%, respectively for PET/CT, 4D-CT, and PET/4D-CT. PET/CT was more sensitive than 4D-CT (p = 0.046). PET/4D-CT performed better than 4D-CT (p = 0.013) but was equivalent to PET/CT alone. On a per gland analysis, sensitivity PET/CT, 4D-CT, and PET/4D-CT was 88%, 66%, and 92%, and DR% was 79%, 57%, and 83%, respectively. PET/CT and PET/4D-CT were more sensitive than 4D-CT alone (p = 0.01, p < 0.001, respectively). However, PET/CT and PET/4D-CT performed similarly. In conclusion, 18F-FCH PET provides better identification of hyperfunctioning parathyroids than 4D-CT and the combination of both did not significantly improve diagnostic sensitivity. Further investigations involving larger populations are necessary to define the role of 18F-FCH PET/4D-CT as a “one-stop shop” second-line imaging in preoperative work-up of pHPT, especially considering the additional patient radiation exposure due to multi-phase CT.

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

Hypocalcaemia is the most common complication after total or completion thyroidectomy. This study assesses recent evidence on predictive factors for post-thyroidectomy hypocalcaemia in order to identify the patients affected and aid prevention. Two authors independently assessed articles and extracted data to provide a narrative synthesis. This study was an updated systematic search and narrative review regarding predictors of post-thyroidectomy hypocalcaemia using the Ovid Medline, Embase, Cochrane and Cinahl databases. Results were limited to papers published from January 2012 to August 2019. Sixty-three observational studies with a total of 210 401 patients met the inclusion criteria. The median incidence was 27.5 per cent for transient biochemical hypocalcaemia, 12.5 per cent for symptomatic hypocalcaemia and 2.2 per cent for permanent hypocalcaemia. The most frequent statistically significant predictor of hypocalcaemia was peri-operative parathyroid hormone level. Symptomatic hypocalcaemia and permanent hypocalcaemia were seen more frequently in patients undergoing concomitant neck dissection. Many factors have been studied for their link to post-thyroidectomy hypocalcaemia, and this study assesses the recent evidence presented in each case.

Prediction of Post Total Thyroidectomy Hypocalcemia Using Perioperative Parathyroid Hormone

Background: hypocalcaemia, which is a major contributing factor for delayed hospital discharge, occurs in many patients following total thyroidectomy. Parathyroid hormone (PTH) measurement has been proposed as a marker of this condition. Aim: the aim of this study was to evaluate the reliability of perioperative parathyroid hormone measurement to predict post-total thyroidectomy hypocalcaemia. Patients and methods: a prospective randomized study was conducted in the period between July 2015 and September 2017 in Ain Shams University, General Surgery Department, Endocrine Surgery Unit, Cairo, Egypt. The study was conducted on sixty patients for whom total thyroidectomy was done. Parathyroid hormone was measured pre-operative and 6 hours postoperative, and serum Ca was measured daily to predict hypocalcaemia. Patients were evaluated for symptoms of hypocalcaemia and treated with calcium and vitamin D supplementation as necessary. Results: the study included 60 patients, 12 males and 48 females with mean age 39.1+ 16.52 (20-65). Co morbid conditions included HTN, DM, ISHD and COPD. Most patients had nodular goiter (48 patients) whether unilateral or bilateral. 63.3% of patients had follicular lesion by FNABC. All patients underwent total thyroidectomy. Hypocalcemia developed in 16.7% (10 of 60) of the patients. Best cut off was 66% reduction giving 77% Sensitivity and 91.4% Specificity. Positive predictive value was 85% and negative predictive value was 94%. Conclusion: the evaluation of PTH and corrected calcium levels 6 hours after thyroidectomy allows for an accurate prediction of the trend of hypocalcemia. This study enables us to discharge most patients safely within 24 hours after total thyroidectomy.

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

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. At our tertiary referral hospital (Luzerner Kantonsspital, Switzerland), atotal of 353patients 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. 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. 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.

Tiroid ve paratiroid cerrahisi sonrası hipokalsemi ve tedavisi

Hypocalcemia is a frequent complication after thyroid and parathyroid surgery. This study aims to evaluate the incidence, pathophysiology, early diagnosis, differential diagnosis, clinical and biochemical predictive factors, treatment of hypocalcemia. Hypocalcemia may be transient, that recovers within 6 months of surgery and permanent that persists more than 6 months after surgery. Postoperative hypocalcemia arises from hypoparathyroidism, hungry bone syndrome, hemodilution due to surgical stress and alkalosis which is caused by hyperventilation due to postoperative pain. The most common cause of postoperative hypocalcemia is hypoparathyroidism. Hypoparathyroidism is characterized by a parathyroid hormone (PTH) deficient leading to hypocalcemia, hyperphosphatemia and hypercalciuria. Postoperative hypoparathroidism occurs usually due to inadvertent or unavoidable the parathyroid gland or damage to it/its blood supply. Hungry bone syndrome can occur after surgery for hyperparathyroidism and Graves disease. The clinical manifestations of postsurgical hypocalcemia depend on the degree of hypocalcemia and rapidity of hypocalcemia onset. The classic symptoms of hypocalcemia is associated with neuromuscular excitability. They vary from numbness and tingling in the fingertips, toes and circumoral region in mild hypocalcemia to paraesthesias of the upper and lower extremities in moderate hypocalcemia. In the most severe forms, tetanic muscle cramps can occur in the form of carpopedal spasm or diffuse tetany. Some cases can occur bronchospasm and laryngospasm. Neurological symptoms such as confusion, disorientation, delirium or seizure, and cardiac abnormalities such as prolonged QT interval on electrocardiogram, arrhythmias, congestive heart failure can also occur. In patients without overt signs, underlying neuromuscular excitability can become evident with provocation tests such as Chvostek’s sign and Trousseau’s sign. Diagnostic workup for hypocalcemia includes measuring serum intact PTH, phosphorus, albumin, magnesium, 25-OH Vit D, and calcium. Clinical predictive factors of hypocalcemia include female sex, inadvertent excision of the parathyroid gland, parathyroid autotransplantation, Graves’ disease, surgery for recurrent goitre, reoperation for bleeding, and heavier thyroid specimens. Perioperative PTH and postoperative changes in calcium levels can be used as biochemical predictors of hypocalcemia. The management of hypocalcemia is best accomplished by identifying high-risk patients preoperatively, preserving function of parathyroid gland during surgery, identifying hypocalcemia via early predictors and implementing appropriate treatment if necessary. Moreover prevention or early identification and appropriate management of hypocalcemia prevents hypocalcemia-related complications and allows patients to be discharged from the hospital earlier. Treatment for hypocalcemia is based on combined theraphy with calcium and vitamin D analoques. Formal guidelines for the management of hypocalcemia are not available. However, there are some common procedures existing in clinical practice. According to the degree and speed onset of hypocalcemia and the severity symptoms, intravenous calcium may be needed until an oral regimen is established. The goal of theraphy is to control hypocalcemic symptoms and achieve and maintain a serum calcium level in the low normal range. The oral dose of calcium and vitamin D analogues should be individually tailored by checking serum calcium, phosphate, and PTH initially every week, and then every 2-3 weeks or monthly. Hypercalcemia must be avoided. New drugs such as recombinant human PTH currently in clinical trials offer promising treatment options.

Perioperative kinetics of parathyroid hormone in unilateral, primary thyroid surgery

Dysfunction of the parathyroid glands is an important cause of complications after thyroid surgery. Intraoperative monitoring of the function of the parathyroid glands can be performed using parathyroid hormone (PTH) kinetics. Unilateral thyroid surgery is associated with a decreased risk for postoperative hypocalcemia (POH) and permanent hypoparathyroidism (PEH). We focused on unilateral thyroid surgery by monitoring the functionality of the parathyroid glands and comparing the perioperative PTH kinetics of patients with and without POH. In a prospective study, 143 patients scheduled for unilateral thyroid surgery underwent monitoring of perioperative changes in serum PTH and serum calcium levels, and of clinical symptoms of hypocalcemia. The rates of POH and PEH were 18.2 and 0%, respectively. In patients without POH, PTH significantly increased from the time of skin incision to the end of the operation and after the operation (20.1 pg/ml, IQR 15.5-26.8 vs. 21.4 pg/ml, IQR 16.4-29.5; p=0.005), which was not the case in patients who developed POH. In a multivariate analysis of predictive factors for POH, two parameters became significant, namely female gender (odds ratio 6.87, 95% confidence interval 0.92-51.01) and lower initial serum calcium levels (odds ratio 3.54*e(-8), 95% confidence interval 3.63*e(-12); 0.00). The rate of POH was unexpectedly high. Rather than intraoperative PTH declines, an unstable balance of factors that influence calcium metabolism likely is the major contributor to POH after unilateral thyroid surgery. There was no case of PEH after unilateral, primary thyroid surgery, which underlines the need for an individualized approach to the extent of resection.

Systematic review and meta-analysis of predictors of post-thyroidectomy hypocalcaemia

Hypocalcaemia is common after thyroidectomy. Accurate prediction and appropriate management may help reduce morbidity and hospital stay. The aim of this study was to perform a systematic literature review and meta-analysis of predictors of post-thyroidectomy hypocalcaemia. A systematic search of PubMed, EMBASE and the Cochrane Library databases was undertaken, and the quality of manuscripts assessed using a modified Newcastle-Ottawa Scale. Some 115 observational studies were included. The median (i.q.r.) incidence of transient and permanent hypocalcaemia was 27 (19-38) and 1 (0-3) per cent respectively. Independent predictors of transient hypocalcaemia included levels of preoperative calcium, perioperative parathyroid hormone (PTH), preoperative 25-hydroxyvitamin D and postoperative magnesium. Clinical predictors included surgery for recurrent goitre and reoperation for bleeding. A calcium level lower than 1·88 mmol/l at 24 h after surgery, identification of fewer than two parathyroid glands (PTGs) at surgery, reoperation for bleeding, Graves' disease and heavier thyroid specimens were identified as independent predictors of permanent hypocalcaemia in multivariable analysis. Factors associated with transient hypocalcaemia in meta-analyses were inadvertent PTG excision (odds ratio (OR) 1·90, 95 percent confidence interval 1·31 to 2·74), PTG autotransplantation (OR 2·03, 1·44 to 2·86), Graves' disease (OR 1·75, 1·34 to 2·28) and female sex (OR 2·28, 1·53 to 3·40). Perioperative PTH, preoperative vitamin D and postoperative changes in calcium are biochemical predictors of post-thyroidectomy hypocalcaemia. Clinical predictors include female sex, Graves' disease, need for parathyroid autotransplantation and inadvertent excision of PTGs.

The Influence of Parathyroidectomy on Restless Legs Syndrome in Patients with Renal Hyperparathyroidism

Restless legs syndrome (RLS) is a common and poorly understood movement disorder that leads to unpleasant leg sensations. Although RLS can be idiopathic, secondary etiologies such as iron deficiency and renal failure are common. The aim of this prospective cohort study was to evaluate whether RLS is a common feature in patients undergoing parathyroidectomy for renal hyperparathyroidism (rHPT) and if RLS-related symptoms can be influenced by surgery. After providing written consent, patients who underwent a parathyroidectomy for rHPT between January and November 2011 answered a validated RLS-screening-questionnaire (RLSSQ). If this was suggestive for RLS a confirming questionnaire (IRLS) was also completed on the day before surgery, on the fifth postoperative day, and again during follow-up (minimum 12 months). Perioperative parathyroid hormone and calcium levels, as well as the scores of the questionnaires were analyzed. Twenty-one patients (14 men, 7 women) with a mean age of 47.8 ± 3.2 years underwent total parathyroidectomy with bilateral cervical thymectomy and parathyroid autotransplantation for rHPT. The mean score of the RLSSQ of all 21 patients prior to operation was 6.1 ± 0.5. In 10 of 21 patients (47.6 %) the results of the RLSSQ were suggestive for RLS with a mean score of 8.0 ± 0.3. The consecutive scores of the IRLS in these latter patients significantly dropped from 26.6 ± 1.4 to 19.0 ± 2.2 between the preoperative and postoperative settings (p < 0.05). After a mean follow-up of 17.3 ± 3.7 months the mean scores of the RLSSQ and the IRLS were 6.1 ± 0.6 and 16.3 ± 1.8. rHPT may play a major role in the severity of RLS-associated symptoms in patients with renal failure. Consequently, parathyroidectomy may prove to be a valuable tool to reduce RLS-associated morbidity in affected patients. However, larger prospective trials are required to confirm the possible relation between RLS and rHPT seen in the present study

Parathyroid hormone: an early predictor of symptomatic hypocalcemia after total thyroidectomy

The purpose of this study was to evaluate if the measurement of peri-operative parathyroid hormone (PTH) is able to identify patients with increased risk of developing symptoms of hypocalcemia. Forty patients who underwent total thyroidectomy were studied prospectively. Ionized serum calcium and PTH were measured after induction of anesthesia, one hour (PTH1) and one day after surgery (PTH24). Patients were evaluated for symptoms of hypocalcemia and treated with calcium and vitamin D supplementation as necessary. Symptomatic hypocalcemia developed in 16 patients. Symptomatic patients had significant lower PTH1 and greater drops in PTH levels. The selection of 12.1 ng/L as PTH1 level cutoff level divided patients with and without symptoms with 93.7% sensitivity and 91.6% specificity. The selection of 73.5% as the cutoff value for PTH decrease resulted in 91.6% sensitivity and 87.5% specificity. PTH1 levels and the drop in PTH levels are reliable predictors of developing symptomatic hypocalcemia after total thyroidectomy.

Cost Analysis of Postthyroidectomy Hypocalcemia

Objective: One of the more common complications following total thyroidectomy is postoperative hypocalcemia. Numerous protocols have been developed over the years for management including perioperative parathyroid hormone (POPTH) levels and obtaining ionized calcium levels postoperatively with supplementation based on the values. Our goal was to perform a cost analysis of POPTH. Method: We examined the postoperative hypocalcemia using ICD-9 codes for thyroid nodules and examined those that underwent total thyroidectomy. We excluded revision surgeries and pathology of cancer. The postoperative PTH values, initial ionized calcium, and number of calcium draws were obtained. The patients were then stratified based on initial PTH value. Results: For initial PTH For initial PTH 21-50, the initial ionized calcium was 3.99 ± 0.38 and the number of laboratory draws was 3.8 ± 3.3. For initial PTH &gt;50, the initial ionized calcium was 4.27 ± 0.37 and the number of laboratory draws was 2.5 ± 1.7. There was no significant difference in the initial ionized calcium between those that had an initial PTH drawn and those that did not. Conclusion: For total thyroidectomies (benign goiter), there was no difference in the initial ionized calcium for PTH90 ( P = .29). This suggests that PTH is not an adequate predictor of postoperative calcium level. Also there is a significant cost burden with obtaining the PTH level where tremendous savings could be achieved.

Kinetics of serum parathyroid hormone during and after thyroid surgery

Hypocalcaemia after thyroidectomy is thought to result from surgical damage to the parathyroid glands. This study analysed postoperative outcomes related to perioperative parathyroid hormone (PTH) levels. Some 402 consecutive patients undergoing thyroid surgery were studied prospectively to monitor perioperative changes in serum PTH and Ca2+ levels, and clinical symptoms of hypocalcaemia. Transient symptomatic hypocalcaemia and persistent hypoparathyroidism occurred in 61 (15 per cent) and six (1.5 per cent) of 402 patients respectively. The intraoperative decline in PTH was 20.2 per cent; the trough (63.8 per cent of preoperative value) was reached 3 h after surgery. Before surgery, PTH levels were correlated inversely with serum Ca2+ concentration. The correlation remained positive from 3 h after surgery until postoperative day 14. Thus, PTH secretion was reduced, but remained sufficient to prevent symptomatic hypocalcaemia in most patients. A low serum PTH level was predictive of persistent hypoparathyroidism (sensitivity and negative predictive value 100 per cent, but poor specificity of 54.1 per cent). Thyroid surgery impairs hormone secretion by the parathyroid glands resulting in postoperative latent parathyroid insufficiency. Normal PTH levels 3 h after surgery and a normal serum calcium level on the first postoperative day rule out persistent hypoparathyroidism.

Prospectives and surgical usefulness of perioperative parathyroid hormone assay in thyroid surgery

Hypocalcemia is the most frequent complication after thyroid surgery. The incidence varies and has been reported as ranging from 1.2 to 40%. Permanent hypoparathyroidism occurs in less than 3% of patients, whereas transient postoperative hypocalcemia is much more common. Postoperative hypoparathyroidism is traditionally detected by serial measurement of serum calcium concentrations and requires multiple venepunctures and, potentially, several days of hospitalization following the procedure. The parathyroid hormone (PTH) molecule is a polypeptide composed of an 84-amino acid sequence with an active amino terminal on one end and an inactive carboxyl unit on the other. Measurement of the intact PTH (iPTH) is an accurate representation of the true parathyroid state. In recent years, iPTH assay has been under investigation for thyroid surgery in many centers as an early iPTH measurement may be of value for prediction of postoperative symptomatic hypocalcemia, guiding the surgeon for parathyroid autotransplatation, and selection of patients requiring onset of calcium substitution or safe discharge home. This paper reviews the relevant medical literature published regarding the influence of PTH assay technology on the quality of thyroid surgery, as well as on the prevention of postoperative symptomatic hypocalcemia. Searches were last updated in April 2008.

Long‐Term Changes in Parathyroid Function After Subtotal Thyroidectomy for Graves’ Disease

Transient hypocalcemia is one of the postoperative complications of thyroidectomy for Graves' disease, and perioperative parathyroid hormone (PTH) assays are used to predict postoperative hypocalcemia. We evaluated long-term changes in parathyroid function after surgery for Graves' disease. Serum PTH values were measured in Graves' patients with postoperative hypocalcemia, and those patients were followed postoperatively. Subtotal thyroidectomy was performed in 275 patients with Graves' disease. Their serum calcium levels were measured on postoperative day (POD) 1, and patients with transient postoperative hypocalcemia were treated with calcium and vitamin D supplementation and followed up. The amount of calcium and vitamin D supplementation was adjusted to keep the patient's serum calcium level within the normal range. Measurement of their serum intact PTH value on POD 1 revealed normal value in 18 patients, a below normal level in 22, and an above normal level in the other 2. During the follow-up period, the serum iPTH values remained normal in 12 patients, recovered to the normal level in 21 patients, and rose above the normal range in 9 patients. The serum iPTH values of all patients eventually reached the normal range during the follow-up period. A marked difference in preoperative serum alkaline phosphatase concentration was observed between the high-iPTH patients and the normocalcemic patients. The phenomenon of an elevated serum PTH level after surgery for Graves' disease was observed in 21% of the patients with postoperative hypocalcemia despite the achievement of normal serum calcium levels by calcium and vitamin D supplementation.

Evidence for the Role of Perioperative PTH Measurement after Total Thyroidectomy as a Predictor of Hypocalcemia

Total thyroidectomy is now accepted worldwide as the standard surgical procedure for the management of benign bilateral nodular thyroid disease. Hypocalcemia is the most common complication of that procedure and a variety of strategies for diagnosing and managing post-thyroidectomy hypocalcemia have been advocated. Increasingly, the use of intact parathyroid hormone (PTH) has been utilized to try to predict those patients at risk of developing post-thyroidectomy hypocalcemia. A Medline search of English language literature was performed and we reviewed the evidence in relation to the following three issues: the accuracy of PTH in predicting hypocalcemia, the optimal timing for measuring PTH, and the routine use of oral calcium supplements. Post-thyroidectomy PTH levels accurately predict hypocalcemia but lack 100% accuracy. Progressive and severe hypocalcemia is unlikely in the setting of a normal PTH level and hence PTH can be cautiously used to facilitate discharge within 24 h for many patients. In addition, PTH levels can be used to implement early treatment with calcium and/or vitamin D supplements to reduce the incidence and severity of hypocalcemia. A single PTH measurement taken any time from 10 min to several hours postoperative will provide equally accurate results for predicting post-thyroidectomy hypocalcemia. Routine use of oral calcium supplements may reduce the incidence and severity of post-thyroidectomy hypocalcemia. Postoperative PTH can be used to stratify the risk of patients developing hypocalcemia after thyroidectomy. In addition, the routine use of oral calcium supplements can lead to decreased incidence and severity of post-thyroidectomy hypocalcemia. Protocols based on PTH and the routine use of oral calcium supplements can lead to improved patient outcomes after thyroidectomy.

Novel Criteria for Parathyroid Hormone Levels in Parathyroid Hormone–Guided Parathyroid Surgery

Novel criteria for decrease of perioperative parathyroid hormone measurement may improve the accuracy of perioperative quick parathyroid hormone (qPTH)-guided parathyroidectomy. To assess overall cure rate based on conventional criteria (50% decline of qPTH). Perioperative qPTH levels were evaluated to determine novel criteria for successful parathyroid surgery. Analysis of perioperative qPTH measurement findings of all consecutive patients undergoing parathyroidectomy for hyperparathyroidism (72 with primary hyperparathyroidism and 28 with secondary or tertiary hyperparathyroidism or multiple endocrine neoplasia I/IIa disease). Measurement of qPTH (based solely on the criterion of greater than 50% decline of parathyroid hormone) in 72 patients with primary hyperparathyroidism (77 procedures) showed true-positive results in 69, false-positive results in 4, and true-negative results in 4 procedures. In our series, false-positive and true-negative results were associated with high postexcision levels. However, when qPTH declines of greater than 70% and 80% were used in cases of postexcision qPTH levels of 100 to 200 ng/L and greater than 200 ng/L, respectively, no false-positive results were observed. Through adherence to these novel criteria, reexploration of the neck could have been prevented in 29% of patients with primary hyperparathyroidism due to multiple gland disease. These novel criteria demand future evaluation to establish their value.