Intra- and postoperative parathyroid hormone-kinetics do not advocate for autotransplantation of discolored parathyroid glands during thyroidectomy

Avoiding Complications of Thyroidectomy: Preservation of Parathyroid Glands

Preservation of functional parathyroid glands during thyroidectomy and central neck surgery is crucial to avoid the common but serious complication of hypoparathyroidism. The first requirement is a solid foundational knowledge of anatomy and embryology which then enables the surgeon to use meticulous anticipatory dissection with identification and preservation of blood supply to the parathyroids. When preservation of blood supply is not possible, autotransplantation should be performed. New technologies harnessing the natural phenomenon of parathyroid autofluorescence to detect parathyroid tissue and indocyanine green to perform angiography may lead to improved outcomes with low risk to patients.

Intraoperative indocyanine green angiography for predicting postoperative hypoparathyroidism

BACKGROUND

Postoperative hypocalcemia is a common complication of thyroidectomy. This problem is most often associated with accidental devascularization or excision of the parathyroid glands (PG).

AIM

Aim was to study near-infrared (NIR) fluorescent imaging with intraoperative PG indocyanine green (ICG) angiography to help identify and preserve PG during total thyroidectomy in order to avoid postoperative hypocalcemia.

MATERIAL AND METHODS

From 2017 to 2022, a total of 92 patients underwent total thyroidectomy at Odessa Regional Hospital. Indications for surgery were multinodular goiter (n = 42), thyroid cancer (n = 43), and Graves' disease (n = 7). By randomization all patients were divided into two groups: in the control group, 48 patients underwent standard total thyroidectomy, and in the main group, 44 patients underwent NIR-assisted total thyroidectomy with ICG angiography. Serum calcium and parathyroid hormone levels were compared between the two groups of patients in 1, 7-15 days after surgery and then 3, 6 months later.

RESULTS

In the control group, based on a visual assessment of the PG, autotransplantation of the PG was conducted in only five cases. In the second group, autotransplantation was performed in 16 patients. The transient postoperative hypocalcemia was observed in 8 patients of the control group (16, 70%) and in the 2 patients of ICG group (4, 50%) on 5-10 postoperative days. In the first group, 2 patients at 3 months after surgery had permanent hypocalcaemia.

CONCLUSION

NIR fluorescent imaging with intraoperative PG ICG angiography is a safe and an easily repeatable method. This technique provides improved detecting and assessment of the perfusion of the PG. The need for autotransplantation of the PG can be determined more objectively using ICG imaging than simple visualization.

Correlation between visual scores and parathyroid function

This mini review summarizes the controversies regarding routine parathyroid identification reviews publications that assess visual scores to predict parathyroid function after thyroidectomy during the pre-ICG era.

Preservation of parathyroid glands during thyroid and neck surgery

The parathyroid glands are situated in close proximity to the thyroid gland. They have an important endocrine function maintaining calcium and phosphate homeostasis in the body by the secretion of parathormone (PTH), which is responsible for this function. The parathyroid glands are commonly damaged during thyroid surgeries. This could lead to transient or permanent hypoparathyroidism in 30% of cases. Preservation of the parathyroid glands, is an important and integral part of thyroidectomy and other surgical interventions in the neck. The main principle underlying this is a thorough understanding of parathyroid anatomy in relation to the thyroid gland and other important structures in the area. There can also be significant variation in the anatomical location of the glands. Various techniques and methods have been described for parathyroid preservation. They include intraoperative identification utilizing indocyanine green (ICG) fluorescence, carbon nanoparticles, loupes, and microscopes. The techniques of surgery (meticulous capsular dissection), expertise, central compartment neck dissection, preoperative vitamin D deficiency, extent and type of thyroidectomy are the risk factors associated with damaged thyroids, inadvertent parathyroidectomy and subsequent hypoparathyroidism. Parathyroid Autotransplantation is a treatment option for inadvertent parathyroidectomy. Ultimately, the best way to assure normal parathyroid function is to preserve them in situ intraoperatively undamaged.

Prevention of hypocalcemia and hypoparathyroidism after total thyroidectomy. Recommendations of the Francophone Association of Endocrine Surgery (AFCE) with the French Society of Endocrinology (SFE) and the French Society of Nuclear Medicine (SFMN)

Postoperative hypoparathyroidism, resulting from removal and/or devascularization of one or more parathyroid glands, is a feared complication of total thyroidectomy. Two forms, which are distinguished by their frequency, their time to onset and their duration as well as by their presentation, must be individualized: early postoperative hypocalcemia, often secondary to early hypoparathyroidism is a frequent and often transient situation occurring within the first days after surgery; permanent hypoparathyroidism, which is rarer, manifests when parathyroid function remains impaired for more than six months after surgery. Because of their severity, these conditions must be known and ideally prevented during total thyroidectomy. The objective of this article is to provide surgeons with practical recommendations for the prevention, diagnosis, and treatment of hypoparathyroidism after total thyroidectomy. These recommendations, which are the fruit of a medico-surgical consensus, were developed by the Francophone Association of Endocrine Surgery (AFCE), the French Society of Endocrinology (SFE) and the French Society of Nuclear Medicine and Molecular Imaging. (SFMN). The content, grade and level of evidence for each recommendation was decided after consultation within a panel of experts, based on an analysis of recent literature.

Indocyanine green fluorescence and near-infrared autofluorescence may improve post-thyroidectomy parathyroid function

BACKGROUND

Near-infrared autofluorescence and indocyanine green fluorescence are 2 recent tools introduced to improve postoperative parathyroid function during thyroid surgery.

METHODS

We conducted a randomized prospective study. Patients undergoing total thyroidectomy were randomly assigned either to the fluorescence group, in which near-infrared autofluorescence and indocyanine green fluorescence were used, or to the control group. The primary outcomes of the study were the rate of postoperative transient and symptomatic hypocalcemia.

RESULTS

A significantly higher number of parathyroid glands were identified in the fluorescence group (3.83 vs 3.64, P = .028). The rate of postoperative symptomatic hypocalcemia was significantly lower in the fluorescence group (6% vs 17%, P = .015), as was the dosage (1.53 vs 1.91 g, P = .007) and the duration of calcium therapy (32.30 vs 45.66 days, P = .003). Having at least 2 well-vascularized parathyroid glands correlates to lower rates of transient hypocalcemia (7.4% vs 21.9%, P = .037) as well as to higher serum calcium (8.70 vs 8.42 mg/dL, P = .027) and parathyroid hormone levels (19.15 vs 11.4 pg/mL, P = .0002) on postoperative day 1.

CONCLUSION

Near-infrared autofluorescence and indocyanine green fluorescence are novel tools that may support the endocrine surgeon in preserving and predicting post-thyroidectomy parathyroid gland function.

Selective Parathyroid Autotransplantation During Total Thyroidectomy for Papillary Thyroid Carcinoma: A Cohort Study

Purpose: The relationship between the selective parathyroid gland (PG) autotransplantation and hypoparathyroidism is still not completely clear. The aim was to ascertain whether the number of autotransplanted PGs affected the incidence of hypoparathyroidism and recovery of parathyroid function in the long-term for patients with papillary thyroid carcinoma (PTC). Methods: A retrospective cohort study included all patients with PTC who had underwent primary total thyroidectomy with central neck dissection between January 2013 and December 2017. The patients were divided into three groups (0, 1, and 2 PGs autotransplanted, respectively). Results: Of the 2,477 patients, 634 (25.6%) received no PG autotransplantation, 1,078 (43.5%) and 765 (30.9%) were autotransplanted 1 and 2 PGs, respectively, and the incidence of permanent hypoparathyroidism (>1 year) was 1.7%, 0.7%, and 0.4% (P = 0.0228). Both 1 or 2 PGs autotransplanted increased the incidence of transient biochemical hypoparathyroidism (odds ratio [OR], 1.567; 95% confidence interval [CI], 1.258-1.953; P < 0.0001; OR, 2.983; 95% CI, 2.336-3.810; P < 0.0001, respectively) but reduced the incidence of permanent hypoparathyroidism (OR, 0.373; 95% CI, 0.145-0.958; P = 0.0404; OR, 0.144; 95% CI, 0.037-0.560; P = 0.0052, respectively). Both 1 or 2 PGs autotransplanted did not independently influence the occurrence of hypocalcemia symptoms. Conclusion: Selective parathyroid autotransplantation is less likely to lead to post-operative symptomatic hypocalcemia, although it could lead to a transient decrease in parathyroid hormone. However, in the long run, it is still an effective strategy to preserve parathyroid function.

Does number of autotransplanted parathyroid glands affects postoperative hypoparathyroidism and serum parathyroid hormone levels?

BACKGROUND

To investigate how number of autotransplanted parathyroid glands (PGs) affects the incidence of postoperative hypoparathyroidism and the recovery of parathyroid function.

METHODS

A systematic search was performed in the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. The evaluated indices included the incidence of postoperative transient and permanent hypoparathyroidism and parathyroid hormone (PTH) levels during follow-up.

RESULTS

Twenty articles with 7291 patients were included. A higher incidence of transient hypoparathyroidism was found in the PG autotransplantation group than in the preservation group (odds ratio [OR]: 2.37; 95% confidence interval [CI]: 1.90, 2.96). However, there was no significant difference between the two groups regarding permanent hypoparathyroidism (OR: 1.17; 95% CI: 0.71, 1.91). Parathyroid hormone (PTH) levels in the PG autotransplantation group changed significantly more than the preservation group at postoperative 1-day and 1-month, but became similar at the 6-month, 1-year and 2-year follow-up. Autotransplantation of 2 and 3 PGs demonstrated a higher incidence of transient hypoparathyroidism than 1 PG (OR: 2.09; 95% CI: 1.41, 3.11 and OR: 9.70; 95% CI: 2.11, 44.39, respectively), but no significant difference was observed between the autotransplantation of 3 and 2 PGs (OR: 0.99; 95% CI: 0.03, 29.06). Additionally, the incidence of permanent hypoparathyroidism was not significantly different when different number of PGs was autotransplanted.

CONCLUSIONS

PG autotransplantation is an effective mid- and long-term strategy for the preservation of parathyroid function. Although transient hypoparathyroidism was positively correlated with the number of autotransplanted PGs, no remarkable correlation was observed for permanent hypoparathyroidism.

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.

Research on Intra-Operative Indocyanine Green Angiography of the Parathyroid for Predicting Postoperative Hypoparathyroidism: A Noninferior Randomized Controlled Trial

OBJECTIVE

A noninferiority randomized controlled trial was undertaken to clarify whether the postoperative measurements of serum calcium and parathyroid hormone and oral supplementation of calcium and calcitriol could be omitted if patients had at least one well-perfused parathyroid gland evaluated by intra-operative indocyanine green (ICG) angiography.

METHODS

Patients with at least one parathyroid gland well-perfused by ICG angiography (ICG score >2) were randomized to the control group or test group. For the control group, oral calcium and calcitriol were systematically supplemented. For the test group, no oral calcium or calcitriol was supplemented to the patients. Levels of serum calcium and parathyroid hormone of patients on the first and 30th postoperative day were compared between the two groups.

RESULTS

Among all 68 selected patients, 56 patients had at least one well-perfused parathyroid gland evaluated by intra-operative ICG angiography. The 56 patients were randomized to the control group or test group. There were no statistically significant differences in the levels of serum calcium and parathyroid hormone between test group and control group on the first or 30th postoperative day.

CONCLUSION

The postoperative measurements of serum calcium and parathyroid hormone and oral supplementation of calcium and calcitriol were evaluated as redundant, if patients had at least one well-perfused parathyroid gland evaluated by intra-operative ICG angiography.

ABBREVIATIONS

ICG = indocyanine green; NIR = near infrared; POD = postoperative day; PTH = parathyroid hormone; SBR = signal background ratio.

Comparison of iPTH and calcium levels between total thyroidectomy and lobectomy: a prospective study of 840 thyroid cancers with three years of follow-up

Background

Hypocalcemia is the most frequent complication after thyroidectomy and central neck dissection (CND). Early intact parathyroid hormone (iPTH) determination has been proposed as an early predictor parathyroid gland state. We aim to describe iPTH kinetics after central compartment lymph node dissection (CLND).

Methods

A large prospective observational study was conducted among 840 patients who underwent thyroid cancer surgery between July and December 2016 in China-Japan Union Hospital of Jilin University. Data were obtained from the patient’s iPTH evaluation 15 min after CND and serum calcium records during three years of post-operative follow-up. Age, sex, BMI, preoperative PTH, operative and pathologic details were analyzed. Backward stepwise logistic regression analyses were performed to find potential risk factors for predicting iPTH <15 pg/mL. The odds ratio and 95% confidence interval are estimated using the logistic regression coefficients. The prediction model was assessed using the receiver operating characteristic curve.

Results

The incidence of permanent hypocalcemia was 0.12%, while, 44.52% of patients were central lymph node metastasis. Multivariate analyses found associations among iPTH <15 pg/mL and several risk factors, especially preop PTH and type of surgery. The risk of iPTH <15 pg/mL, after total thyroidectomy plus CND, is almost 17 times that of lobectomy plus CND (OR =17.648, 95% confidence interval: 10.011–31.110). A model was created using multivariate analysis, which involved surgical procedure, and preop PTH could separate thyroid operation with iPTH <15 pg/mL. The biological index showed an area under the ROC curve of 0.697 and 0.613 separately. Using values below the lowest or above the highest cut-off point, the presence or absence of iPTH <15 pg/mL could possibly be predicted before thyroidectomy and CND.

Conclusions

A lobectomy procedure for papillary thyroid carcinoma patients with clinically uninvolved neck lymph nodes (cN0) who have primary tumors (T1 or T2) could accompany prophylactic CND (ipsilateral or bilateral) to provide clearance of disease compared to 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.

[Modern thyroid surgery - the surgeon's endocrine-surgical understanding and his responsibility for the extent of surgery and complication rate]

Die hohe Qualität der Schilddrüsenchirurgie impliziert ein endokrin-chirurgisches Verständnis des Operateurs mit dem Ziel einer bestmöglichen Ergebnisqualität. Das beinhaltet ein befundadäquates Resektionsausmaß und eine möglichst niedrige Komplikationsrate. Der Chirurg sollte frühzeitig in die Operationsindikation eingebunden sein und auch selbst die Diagnostik, speziell den Schilddrüsen- und Halslymphknotenultraschall, sowie die Interpretation der Schnittbild- und nuklearmedizinischen Verfahren beherrschen. Im Besonderen sollte er über zeitgemäße Radikalitätsprinzipien in der Chirurgie Bescheid wissen.

Bei der gutartigen Struma ist eine individualisierte Operationsstrategie anzuwenden: Solitärknoten können auch einer gewebeschonenden Knotenresektion unterzogen werden. Bei multinodulärer Knotenstruma ist nicht zwingend eine totale Thyreoidektomie notwendig, die Vermeidung eines permanenten Hypoparathyreoidismus hat Priorität. Bei Rezidivstrumen ist oft die einseitige Operation des dominanten Befundes zu bevorzugen. Auch besteht zunehmend der Trend, die Indikation zur Entfernung der Schilddrüsenlappen seitengetrennt zu stellen. Die Basedow Struma erfordert eine Thyreoidektomie. Auch die hypertrophe Thyreoiditis Hashimoto kann eine Operationsindikation darstellen.

Die Radikalitätsprinzipien bei maligner Struma haben sich ebenfalls deutlich gewandelt als auch die strenge Indikation zur Radiojodtherapie. Das gilt speziell für papilläre Mikrokarzinome und minimal invasive follikuläre Tumortypen. Selbst bei medullären Schilddrüsenkarzinom stehen die Radikalitätsprinzipien im Hinblick auf synchrone oder metachrone laterale Halsdissektion in Diskussion.

Der Hypoparathyreoidismus stellt derzeit das Hauptproblem in der radikalen Schilddrüsenchirurgie dar. Recurrensparese und Nachblutung sind durch die subtile Operationstechnik selten geworden. Spezielle extrazervikale Operationszugänge sind nach wie vor in der Erprobungsphase und unter strengen Studienbestimmungen nur Zentren vorbehalten. Die Radiofrequenzablation stellt für gewisse Läsionen wie Zysten und autonome Adenome bei chirurgischer Kontraindikation ein alternatives Ablationsverfahren dar.

Outcomes of parathyroid gland identification and autotransplantation during total thyroidectomy

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Main Surgical Principles and Methods in Surgical Treatment of Primary Hyperparathyroidism

The only curative treatment for primary hyperparathyroidism (pHPT) is surgery. The most important factors that increase the success rate of a parathyroidectomy are the establishment of the correct diagnosis and the surgeon's good knowledge of anatomy and embryology. The lower parathyroid glands develop from the dorsal portion of the third pharyngeal pouch, and the upper parathyroid glands from the fourth pharyngeal pouch. Humans typically have 4 parathyroid glands; however, more than 4 and fewer than 4 have been observed. Typically, the upper parathyroid glands are located in the cricothyroid junction area on the posterolateral portion of the middle and upper third of the thyroid, while the lower parathyroids are located in an area 1 cm in diameter located posterior, lateral, or anterolateral to the lower thyroid pole. Ectopic locations of parathyroid glands outside the normal anatomical regions due to the abnormal migration during embryological development or acquired ectopy due to migration of enlarged parathyroids are not uncommon. There are various surgical techniques to treat HPT; however, 2 main surgical options are used: bilateral neck exploration (BNE) and minimally invasive parathyroidectomy (MIP). While there are open, endoscopic, and video-assisted MIP (MIVAP) approaches, most often an open lateral MIP technique is used. In addition, endoscopic or robotic parathyroidectomy methods performed from remote regions outside the neck have been reported. Although currently MIP is the standard treatment option in selected patients with positive imaging, BNE remains the gold standard procedure in parathyroid surgery. In 80% to 90% of patients with pHPT, a pathological parathyroid gland can be detected with preoperative imaging methods and MIP can be applied. However, the pathological gland may not be found during a MIP procedure as a result of false positive results. The parathyroid surgeon must also know the BNE technique and be able to switch to BNE and change the surgical strategy if necessary. If the intended gland is not found in its normal anatomical site, possible embryological and acquired ectopic locations should be investigated. It should be kept in mind that MIP and BNE are not alternatives to each other, but rather complementary techniques for successful treatment in parathyroid surgery.

Hypoparathyroidism After Total Thyroidectomy: Importance of the Intraoperative Management of the Parathyroid Glands

BACKGROUND

Total thyroidectomy is the most common surgical procedure for the treatment of thyroid diseases. Postoperative hypocalcemia/hypoparathyroidism is the most frequent complication after total thyroidectomy. The aim of this study was to evaluate the rate of postoperative hypocalcemia and permanent hypoparathyroidism after total thyroidectomy in order to identify potential risk factors and to evaluate the impact of parathyroid autotransplantation.

PATIENTS AND METHODS

We performed a retrospective analysis of 1018 patients who underwent total thyroidectomy at our institution between 2000 and 2016. Medical records were reviewed to analyze patient features, clinical presentation, management and postoperative complications. Descriptive and inferential statistics were employed based on the natural scaling of each included variable. Statistical significance was set at p ≤ 0.05.

RESULTS

Mean ± SD age was 46.79 ± 15.9 years; 112 (11.7%) were males and 844 (88.3%) females. A total of 642 (67.2%) patients underwent surgery for malignant disease. The rate of postoperative hypocalcemia, transient, protracted and permanent hypoparathyroidism was 32.8%, 14.43%, 18.4% and 3.9%, respectively. Permanent hypoparathyroidism was significantly associated with the number of parathyroid glands remaining in situ (4 glands: 2.5%, 3 glands: 3.8%, 1-2 glands: 13.3%; p ˂ 0.0001) [OR for 1-2 glands in situ = 5.32, CI 95% 2.61-10.82]. Other risk factors related to permanent hypoparathyroidism were obesity (OR 3.56, CI 95% 1.79-7.07), concomitant level VI lymph node dissection (OR 3.04, CI 95% 1.46-6.37) and incidental parathyroidectomy without autotransplantation (OR 3.6, CI 95% 1.85-7.02).

CONCLUSIONS

Identification and in situ preservation of at least three parathyroid glands were associated with a lower rate of postoperative hypocalcemia (30.4%) and permanent postoperative hypoparathyroidism (2.79%).

Postoperative Hypoparathyroidism in Thyroid Surgery: Anatomic-Surgical Mapping of the Parathyroids and Implications for Thyroid Surgery

Hypoparathyroidism remains one of the most common complications in thyroid surgery. This study aims for an improved understanding of the complexity of the blood supply and the localisation of the parathyroids compared to the two most important intraoperative landmarks: the inferior laryngeal nerve (ILN) and Zuckerkandl's tubercle (ZT). We examined 103 laryngeal compounds to classify the blood supply and the localisation of the parathyroids. For intraoperative localisation we defined a Cartesian coordinate system with the ZT plane as x-axis and the course of the inferior laryngeal nerve as y-axis. The inferior thyroid artery (ITA) mainly supplies the parathyroids, whereas the superior thyroid artery provides a backup supply. It must be pointed out that 8.2% of parathyroids receive their blood directly from the thyroid gland. 73.5% of all parathyroids lie within 1 cm of the ILN and 1 cm cranial and 2.5 cm caudal to the ZT plane. Our described perimeters mark the most crucial areas during surgery and provide the surgeon with an anatomic mapping showing areas of special carefulness needed. One should keep bearing in mind all possible blood supply types of the parathyroids and therefore all branches should be handled with care.

FIRST DAY SERUM CALCIUM AND PARATHYROID HORMONE LEVELS AS PREDICTIVE FACTORS FOR SAFE DISCHARGE AFTER THYROIDECTOMY

Context

Permanent hypocalcemia is a rare but significant complication of thyroid surgery.

Objective

The aim of this study was to identify predictive factors of hypocalcemia and hypoparathyroidism after thyroidectomy.

Design

Study included 134 total patients submitted to thyroidectomy from two endocrine units (January 2015 - August 2016).

Methods

We measured total serum calcium (sCa) and intact PTH (iPTH) on postoperative day one and 1 month after surgery.

Results

118 patients were women with F/M ratio of 7.3/1 and a mean age of 51.8 years. 64 patients were included in group A (iPTH <12 pg/mL) and 70 patients in group B (iPTH >12 pg/mL). sCa and hypocalcemia symptoms were correlated with iPTH, measured 24 hours after surgery. The cut-off value was for sCa 8.05 mg/dL with a sensitivity of 85.29% and a specificity of 88.0% and for iPTH 11.2 pg/mL, with a sensitivity of 82.3% and a specificity of 71.0%. SCa (< 8.05 mg/dL) was a predictive factor with a 99 (IC95%:12.86-761.58) and iPTH (<11.2 pg/mL) with a 10.77 higher risk (CI95%: 3.83-30.30) to be associated with symptoms.

Conclusion

SCa and iPTH represent good predictive factors of early and safe hospital discharge and can predict the risk of prolonged and permanent hypoparathyroidism.

Intraoperative Decision Making in Parathyroid Surgery

This article reviews intraoperative decision making related to several important aspects of parathyroid surgery. These include how to systematically identify a missing gland, when to perform a unilateral versus bilateral exploration for cure, approaches to secondary hyperparathyroidism, management of familial hyperparathyroidism, and the treatment of parathyroid cancer. The management of intraoperative complications, such as recurrent laryngeal nerve injury and devascularization of parathyroid glands, also is discussed.

Developing a Clinical Prototype to Guide Surgeons for Intraoperative Label-Free Identification of Parathyroid Glands in Real Time

BACKGROUND

Patients undergoing thyroidectomy may have inadvertent damage or removal of the parathyroid gland(s) due to difficulty in real-time parathyroid identification. Near-infrared autofluorescence (NIRAF) has been demonstrated as a label-free modality for intraoperative parathyroid identification with high accuracy. This study presents the translation of that approach into a user-friendly clinical prototype for rapid intraoperative guidance in parathyroid identification.

METHODS

A laboratory (lab)-built spectroscopy system that measures NIRAF in tissue was evaluated for identifying parathyroid glands in vivo across 162 patients undergoing thyroidectomy and/or parathyroidectomy. Based on these results, a clinical prototype called PTeye was designed with a user-friendly interface and subsequently investigated in 35 patients. The performance of the lab-built system and the clinical prototype were concurrently compared side by side by a single user with 20 patients in each group. The influence of (i) intrapatient and interpatient variability of NIRAF in thyroid and parathyroid glands and (ii) thyroid and parathyroid pathology on intraoperative parathyroid identification were investigated. The effect of blood on NIRAF intensity of parathyroid and thyroid was tested ex vivo with the PTeye system to assess if a hemorrhagic surgical field would affect parathyroid identification. Accuracy of both systems were determined by correlating the acquired data with either visual confirmation by a surgeon for unexcised parathyroid glands or histology reports for excised parathyroid glands.

RESULTS

The overall accuracy of the lab-built system in guiding parathyroid identification was 92.5%, while the PTeye system achieved an accuracy of 96.1%. Unlike the lab-built system, the PTeye could guide parathyroid identification even as the operating room lights remained on and required only 25% of the laser power used by the lab-built setup. Parathyroid glands had elevated NIRAF intensity compared to thyroid and other neck tissues, regardless of thyroid or parathyroid pathology. Blood did not seem to affect tissue NIRAF measurements obtained with both systems.

CONCLUSION

In this study, the clinical prototype PTeye demonstrated high accuracy for label-free intraoperative parathyroid identification. The intuitive interface of the PTeye that can guide in identifying parathyroid tissue in the presence of ambient room lights suggests that it is a reliable and easy-to-use tool for surgical personnel.

Predictors of postoperative hypocalcemia occurring after a total thyroidectomy: results of prospective multicenter study

BACKGROUND

Thyroid surgeries are among the most common operations performed in the world. Hypocalcemia following total thyroidectomy is a common complication that is sometimes difficult to correct. The aim of this study is to determine the risk factors for hypocalcemia following total thyroidectomy and their clinical value.

METHODS

From January 2015 through to April 2017, 400 patients were included in this prospective multicenter study. All patients underwent total thyroidectomy due to various thyroid diseases. The following risk factors were analyzed: pre-operative and post-operative biochemical blood parameters, clinical effects and factors related to surgery, the patient, and the disease.

RESULTS

Post-operative hypocalcemia developed in 257 patients (64.2%). Of them, 197 patients (76.7%) were diagnosed with asymptomatic hypocalcemia. Clinical symptoms were present in 60 of the 257 patients with hypocalcemia (23.3%). The statistically significant predictors of hypocalcemia were decreased calcium and ionized calcium pre-operatively (p < 0.001), parathyroid hormone on day one following surgery (p < 0.001), thyrotoxicosis <10 years before surgery (odds ratio 1.65, 95% CI 1.01-2.70, p = 0.046), the number of parathyroid glands found during surgery (odds ratio 0.52, 95% CI 0.38-0.70, p < 0.001), ligation of the trunk of the left inferior thyroid artery (odds ratio 2.04, 95% CI 1.27-3.29, p = 0.003), ligation of the trunk of the right inferior thyroid artery (odds ratio 2.37, 95% CI 1.47-3.81, p < 0.001), and the number of transplanted parathyroid glands (odds ratio 1.87, 95% CI 1.12-2.97, p = 0.015). In the multivariate analysis, age (odds ratio 1.05, 95% CI 1.01-1.09, p = 0.029) and gender (odds ratio 5.94, 95% CI 1.13-31.26, p = 0.035) were statistically significant predictors.

CONCLUSIONS

This study demonstrates that there is a number of different patient (gender, age, and duration of thyrotoxicosis <10 years before surgery) and surgical (number of parathyroid glands found during surgery, decreased calcium and ionized calcium before surgery, parathyroid hormone on day one following surgery, and ligation of the trunk of the left and right inferior thyroid artery) risk factors predictive of hypocalcemia following total thyroidectomy. Optimization of the surgical technique could possibly prevent the occurrence of hypocalcemia after total thyroidectomy in some cases; in other cases, identification of known risk factors post-operatively could permit early detection and effective treatment of these patients.

American Thyroid Association Statement on Postoperative Hypoparathyroidism: Diagnosis, Prevention, and Management in Adults

BACKGROUND

Hypoparathyroidism (hypoPT) is the most common complication following bilateral thyroid operations. Thyroid surgeons must employ strategies for minimizing and preventing post-thyroidectomy hypoPT. The objective of this American Thyroid Association Surgical Affairs Committee Statement is to provide an overview of its diagnosis, prevention, and treatment.

SUMMARY

HypoPT occurs when a low intact parathyroid hormone (PTH) level is accompanied by hypocalcemia. Risk factors for post-thyroidectomy hypoPT include bilateral thyroid operations, autoimmune thyroid disease, central neck dissection, substernal goiter, surgeon inexperience, and malabsorptive conditions. Medical and surgical strategies to minimize perioperative hypoPT include optimizing vitamin D levels, preserving parathyroid blood supply, and autotransplanting ischemic parathyroid glands. Measurement of intraoperative or early postoperative intact PTH levels following thyroidectomy can help guide patient management. In general, a postoperative PTH level <15 pg/mL indicates increased risk for acute hypoPT. Effective management of mild to moderate potential or actual postoperative hypoPT can be achieved by administering either empiric/prophylactic oral calcium and vitamin D, selective oral calcium, and vitamin D based on rapid postoperative PTH level(s), or serial serum calcium levels as a guide. Monitoring for rebound hypercalcemia is necessary to avoid metabolic and renal complications. For more severe hypocalcemia, inpatient management may be necessary. Permanent hypoPT has long-term consequences for both objective and subjective well-being, and should be prevented whenever possible.

Parathyroid Autotransplantation During thyroid Surgery. Where we are? A Systematic Review on Indications and Results

Introduction: Hypoparathyroidism still represents an important concern in thyroid surgery. Careful dissection with identification and preservation of parathyroid glands in situ remains the best way to maintain gland vitality and avoid post-operative failure. Nevertheless, parathyroid glands are still inadvertently removed in up to 11% of cases. Parathyroid autotransplantation may represent the only way to restore parathyroid gland functionality in case of inadvertent removal or devascularization during thyroid surgery. Despite this, there is still no agreement on the effectiveness of this procedure. The present systematic review is focused on the mainly debated matters regarding the procedure, indications, technique and results. Methods: This review has been carried out according to PRISMA statement and checklist. The research item was: (((parathyroid autotransplantation[Title]) OR parathyroid reimplantation[Title]) NOT hyperparathyroidism[Title]) AND english[Language]. Results: A total of 31 studies have been found according to limitations already described, reporting from 4 to 890 procedures, with a total amount of 4088 PA. Among these studies, there are only 7 prospective case-series evaluations, 2 prospective randomized trials, while the other 22 studies are retrospective evaluations. The main concerns are: when and how to perform autotransplantation; in which anatomical site; which result to be expected, and how to manage and control the graft. Conslusions: Parathyroid autotransplantatin is an important tool to avoid or minimize the risk for hypoparathyroidism following thyroid surgery in selected cases. Parathormone assay can help the surgeon to determine when reimplantation is indicated or not. Further studies could theoretically give definitive results.

Randomized clinical trial of intraoperative parathyroid gland angiography with indocyanine green fluorescence predicting parathyroid function after thyroid surgery

BACKGROUND

Hypoparathyroidism, the most common complication after thyroid surgery, leads to hypocalcaemia and significant medical problems. An RCT was undertaken to determine whether intraoperative parathyroid gland angiography with indocyanine green (ICG) could predict postoperative hypoparathyroidism, and obviate the need for systematic blood tests and oral calcium supplementation.

METHODS

Between September 2014 and February 2016, patients who had at least one well perfused parathyroid gland on ICG angiography were randomized to receive standard follow-up (measurement of calcium and parathyroid hormone (PTH) on postoperative day (POD) 1 and systematic supplementation with calcium and vitamin D; control group) or no supplementation and no blood test on POD 1 (intervention group). In all patients, calcium and PTH levels were measured 10-15 days after thyroidectomy. The primary endpoint was hypocalcaemia on POD 10-15.

RESULTS

A total of 196 patients underwent ICG angiography during thyroid surgery, of whom 146 had at least one well perfused parathyroid gland on ICG angiography and were randomized. None of these patients presented with hypoparathyroidism, including those who did not receive calcium supplementation. The intervention group was statistically non-inferior to the control group (exact 95 per cent c.i. of the difference in proportion of patients with hypocalcaemia -0·053 to 0·053; P = 0·012). Eleven of the 50 excluded patients, in whom no well perfused parathyroid gland could be identified by angiography, presented with hypoparathyroidism on POD 1, and six on POD 10-15, which was significantly different from the findings in randomized patients (P = 0·007).

CONCLUSION

ICG angiography reliably predicts the vascularization of the parathyroid glands and obviates the need for postoperative measurement of calcium and PTH, and supplementation with calcium in patients with at least one well perfused parathyroid gland. Registration number: NCT02249780 (http://www.clinicaltrials.gov).

Parathyroid autotransplantation in thyroid surgery

BACKGROUND

Careful parathyroid gland dissection and in situ preservation was the time-honored approach to prevent parathyroid failure after total thyroidectomy. The relative success of parathyroid autotransplantation of hyperplastic parathyroid tissue in patients with renal or hereditary hyperparathyroidism did popularize the use of normal parathyroid tissue autografts during thyroidectomy to prevent permanent hypoparathyroidism. Proof of autograft function in this setting, however, is controversial.

PURPOSE

This narrative review aims at reviewing critically the current status of parathyroid autotransplantation during total thyroidectomy. It is also meant to analyze from the historical, methodological, and clinical points of view the claimed benefit of normal parathyroid gland autotransplantation. A focus is placed on the prevention of permanent hypoparathyroidism by parathyroid autotransplantation.

CONCLUSIONS

Liberal parathyroid autotransplantation was proposed in the mid 1970s but evidence of function is scarce. Proofs are accumulating that parathyroid autografts not only increase the rate of postoperative hypocalcemia, but may be also contribute to permanent hypoparathyroidism.

Does the number of parathyroid glands autotransplanted affect the incidence of hypoparathyroidism and recovery of parathyroid function?

BACKGROUND

The relationship between the number of parathyroid glands autotransplanted and hypoparathyroidism as well as recovery of parathyroid function is not understood fully. The aim was to ascertain whether the number of autotransplanted glands affected the incidence of hypoparathyroidism and recovery of parathyroid function in long-term follow-up after thyroidectomy.

METHODS

A retrospective cohort study included all patients with papillary thyroid carcinoma who underwent first-time total thyroidectomy with central neck dissection between June 2012 and June 2015. The patients were divided into 4 groups (0, 1, 2, and 3) on the basis of the number of parathyroid glands autotransplanted.

RESULTS

Of the 766 patients, 283 (36.9%) had no gland autotransplanted, and 373 (48.7%), 97 (12.7%), and 13 (1.7%) had 1, 2, and 3 glands autotransplanted, respectively. More lymph nodes and more metastatic ones in the central compartment were retrieved in groups 2 and 3 (P < .05). With increasing number of autotransplanted glands, the incidence of transient hypoparathyroidism was 26.1%, 36.2%, 52.6%, and 84.6% (P < .05), and the incidence of permanent hypoparathyroidism was 1.8%, 1.1%, 1.0%, and 0% (P > .05). The recovery rates of serum parathyroid hormone concentration were 84.7%, 82.2%, 82.0%, and 79.2% after 2-year follow-up (P > .05).

CONCLUSION

Autotransplantation is an effective strategy for restoration of parathyroid function. Transient hypoparathyroidism is positively correlated to the number of autotransplanted parathyroid glands during total thyroidectomy with central neck dissection. There is no increase in permanent hypoparathyroidism in patients with a higher number of autotransplanted glands, despite more extensive lymph node disease. (Surgery 2018;161:XXX-XXX.).

In Situ Preservation Fraction of Parathyroid Gland in Thyroidectomy: A Cohort Retrospective Study

BACKGROUND AND OBJECTIVES

Parathyroid failure is the most common symptom after thyroidectomy. To prevent it, a gland was preserved in situ or an ischemic one was autotransplanted. This study explored the relationship between in situ preservation of the parathyroid gland and gland failure.

METHODS

Consecutive patients who underwent initial total thyroidectomy were enrolled retrospectively in a prospectively maintained database. Patients were divided into groups by parathyroid gland remaining in situ fraction (PGRIF) (PGRIF = number of in situ glands/(total number of identified glands - number of glands in specimen). Patients were graded by tertiles and followed at least one year after surgery.

RESULTS

559 patients were included. PGRIF is significantly inversely associated with transient hypoparathyroidism, protracted hypoparathyroidism, and postoperative hypocalcemia. PGRIF was identified as an independent risk factor for transient hypoparathyroidism, protracted hypoparathyroidism, and postoperative hypocalcemia (OR = 0.177, 0.190, and 0.330, resp.). Autotransplantation of parathyroid gland would not affect the calcium level in the long term.

CONCLUSION

In situ preservation of parathyroid gland is crucial for parathyroid function. Less preserved is the independent risk factor for postoperative hypoparathyroidism and hypocalcemia, resulting in a worse function of parathyroid gland in the long term.

To identify or not to identify parathyroid glands during total thyroidectomy

Hypoparathyroidism is one of the most common complications after total thyroidectomy and may impose a significant burden to both the patient and clinician. The extent of thyroid resection, surgical techniques, concomitant central neck dissection, parathyroid gland (PG) autotransplantation and inadvertent parathyroidectomy have long been some of the risk factors for postoperative hypoparathyroidism. Although routine identification of PGs has traditionally been advocated by surgeons, recent evidence has suggested that perhaps identifying fewer number of in situ PGs during surgery (i.e., selective identification) may further lower the risk of hypoparathyroidism. One explanation is that visual identification may often lead to subtle damages to the nearby blood supply of the in situ PGs and that may increase the risk of hypoparathyroidism. However, it is worth highlighting the current literature supporting either approach (i.e., routine vs. selective) remains scarce and because of the significant differences in study design, inclusions, definitions and management protocol between studies, a pooled analysis on this important but controversial topic remains an impossible task. Furthermore, it is worth nothing that identification of PGs does not equal safe preservation, as some studies demonstrated that it is not the number of PGs identified, but the number of PG preserved in situ that matters. Therefore a non-invasive, objective and reliable way to localize PGs and assess their viability intra-operatively is warranted. In this aspect, modern technology such as the indocyanine green (ICG) as near-infrared fluorescent dye for real-time in situ PG perfusion monitoring may have a potential role in the future.

A reappraisal of vascular anatomy of the parathyroid gland based on fluorescence techniques

Identification of the parathyroid glands (PGs) during thyroid surgery may prevent their inadvertent surgical removal and prevent postoperative hypoparathyroidism. However, identification of the PGs does not guarantee their function, and their vascular supply needs to be preserved as well. The recent introduction of intraoperative indocyanine green (ICG) fluorescent angiography of the PGs during thyroid surgery allows for the appraisal of the vascular anatomy and evaluation of PG function. The use of this tool could lead to a significant reduction in the rate of postoperative hypoparathyroidism, as it allows surgeons to adapt their surgical technique for the preservation of the PGs. ICG fluorescent angiography is currently the only available real-time tool to assess the vascular blood supply of each individual PG intraoperatively and can thus assist surgeons in their decision-making. Herein, we review the relevant literature.

The PGRIS and parathyroid splinting concepts for the analysis and prognosis of protracted hypoparathyroidism

Most patients with hypocalcemia after total thyroidectomy will recover the parathyroid function in a few weeks, but some 20-30% of them will still be in the need for replacement therapy one month after surgery and about 5-10% of those will develop permanent hypoparathyroidism. Although postoperative hypocalcemia has been related to several demographic and metabolic causes, parathyroid hormone (PTH) decline, resulting from autotransplantation, inadvertent excision or devascularization of the parathyroid glands, is the common final pathway. The number of parathyroid glands remaining in situ (PGRIS) is a key variable to understand the pathogenesis of protracted hypoparathyroidism and the chances for restoration of the parathyroid function. Normal-high serum calcium concentration, probably achieved by a more intensive medical treatment at the time of hospital discharge, has been identified as an independent variable favoring recovery of the parathyroid function. This we refer to as parathyroid splinting, a hypothesis holding that putting the injured parathyroid parenchyma at rest after thyroidectomy may improve long-term outcome of protracted hypoparathyroidism.

PARATHYROID FUNCTION AFTER TOTAL THYROIDECTOMY: A RANDOMIZED CLINICAL TRIAL CONCERNING THE INFLUENCE OF THE SURGICAL TECHNIQUE

OBJECTIVE

Thyroidectomy impairs parathyroid function, even if it does not necessarily lead to postoperative clinical hypocalcemia. This study was prospective and evaluated the parathyroid hormone (PTH) function in nonclinically symptomatic patients after total thyroidectomy performed by two different techniques.

METHODS

Prospective randomized clinical trial including 269 patients undergoing classic or harmonic scalpel total thyroidectomy. Pre-operatively and at 48 hours, biochemical analysis was performed. Simultaneously, a sodium bicarbonate test (SBT) was performed.

RESULTS

Calcium and PTH were altered for both groups ( P<.001). During SBT at 3 minutes after infusion, PTH rose and reached its maximum for both groups ( P<.001) and then decreased at 5 minutes ( P<.001 and P = .004) and at 10 minutes ( P = .006 and P = .043) before returning to baseline levels. At 5 and 10 minutes of the SBT, some differences were observed between the groups. The difference in clinically obvious parathyroid dysfunction between groups was not significant, but there was a difference in the peak PTH levels after bicarbonate stimulation. Similarly, total secretion during the test, as well as total secretion for the first 10 minutes, was practically the same for the two groups. Additionally, partial subclinical postoperative hypoparathyroidism was clearly more common in the harmonic scalpel thyroidectomy group ( P<.001).

CONCLUSION

SBT demonstrated more impairment in the harmonic scalpel group, as parathyroid function was altered after thyroidectomy.

ABBREVIATIONS

HSTT = harmonic scalpel total thyroidectomy PTH = parathyroid hormone SBIT = sodium bicarbonate infusion test.

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.

Parathyroid score can predict the duration of required calcium supplementation after total thyroidectomy

BACKGROUND

Postoperative hypoparathyroidism is the most common complication after total thyroidectomy, owing to unintentional injury or decreased blood flow to the parathyroid glands. Prediction of postoperative hypoparathyroidism would be helpful for surgeons to manage postoperative hypocalcemia. In this study, we scored the discoloration of the parathyroid glands using a new parathyroid scoring system and evaluated the correlation between the parathyroid score and duration of required calcium supplementation after total thyroidectomy.

METHODS

A total of 316 patients undergoing total thyroidectomy between November 2009 and April 2010 were enrolled in this retrospective study. Parathyroid scoring was performed by one experienced surgeon. The status of each of the 4 parathyroid glands was classified as normal color (3 points), slightly discolored (2 points), dark discoloration (1 point), or loss of the gland (0 points), resulting in possible total scores of 0-12. Serum parathyroid hormone (PTH), serum calcium, and ionized calcium concentrations were measured at 2 hours, 2 weeks, 3 months, 6 months, and 1 year after surgery. Patients were also divided into three groups based on the duration of required calcium supplementation: no required supplementation (n = 260, 82.3%), required supplementation for <6 months (n = 38, 12%), and required supplementation for ≥6 months (n = 18, 5.75%).

RESULTS

Parathyroid scores were positively correlated with ionized PTH concentrations at 2 hours (r = 0.053, p < 0.001), 2 weeks (r = 0.056, p < 0.001), 3 months (r = 0.032, p<0.001), 6 months (r = 0.072, p < 0.001), and 1 year (r = 0.071, p < 0.001) after thyroidectomy. Parathyroid scores were significantly and inversely associated with the duration of required calcium supplementation (p = 0.001).

CONCLUSIONS

Parathyroid scores at the end of surgery might be helpful for predicting the degree of postoperative hypocalcemia after total thyroidetomy.

The Association of Discolored Parathyroid Glands and Hypoparathyroidism Following Total Thyroidectomy

BACKGROUND

It remains uncertain whether a parathyroid gland (PG) that appears darkened or severely bruised but still has an attached vascular pedicle should be left in situ or taken out and auto-transplanted following total thyroidectomy. Our study aimed to examine the impact of discolored PGs (DPGs) on short- and long-term hypoparathyroidism.

METHODS

One hundred and three patients who underwent total thyroidectomy with 4 clearly identified PGs were analyzed. Location (superior/inferior) and color of each PG were recorded. Patients without DPG were grouped into I while those with 1-2 DPGs and ≥3 DPGs were grouped into II and III, respectively. Transient hypoparathyroidism meant adjusted Ca <2.00 mol/L 24 h after surgery and/or need for supplements. Protracted hypoparathyroidism meant a subnormal PTH at 4-6 weeks and/or supplements >6 weeks. Permanent hypoparathyroidism meant supplements ≥1 year.

RESULTS

Relative to I, group III had greater adjusted Ca drop at postoperative 1-h (p = 0.012), 24-h (p < 0.001) and lower day-1 PTH (p = 0.015). Having ≥3 DPGs (OR 14.00, 95 % CI 1.575-124.474, p = 0.018) was an independent factor of transient hypoparathyroidism. However, permanent hypoparathyroidism rate was higher than in group I than II (p = 0.019). Eight patients (25.8 %) in group I had undetectable day-1 PTH, while none in group III had undetectable day-1 PTH. Graves' disease/toxic goiter (OR 15.166, 95 % CI 2.594-88.661, p = 0.003) and excised gland weight (OR 1.028, 95 % CI 1.010-1.046, p = 0.003) were independent factors of ≥3 DPGs.

CONCLUSIONS

PG discoloration is associated with transient hypoparathyroidism while normal colored PG with seemingly adequate blood supply does not always imply functionally normal gland. These findings highlights the need for a real-time intraoperative method to assess PG viability.

The Preservation and Autotransplantation of the Parathyroid Glands in Total Thyroidectomy in Patients With Thyroid Cancer—A Strategy for Avoiding Permanent Hypoparathyroidism

Hypoparathyroidism is a complication that occurs after total thyroidectomy (TT) in patients with thyroid cancer. We tried to determine a strategy for avoiding permanent hypoparathyroidism. A total of 42 patients underwent TT for thyroid cancer between April 2009 and March 2014. One or more parathyroid glands (PGs) could be macroscopically preserved in all of the patients. First, we evaluated the association between the number of PGs that were macroscopically preserved and the postoperative course in 28 patients without autotransplantation. The number of preserved PGs was not associated with postoperative tetany or the serum levels of calcium or phosphorous on postoperative day 1, or the proportion of patients who needed to take calcium supplements or a vitamin D analog. However, only the patients with a single preserved PG required calcium supplementation for longer than 1 year (33.3%, P &lt; 0.05). Next, we compared the clinical course with PG autotransplantation in 16 patients in whom a single PG was preserved. Although the result was not statistically significant, only the patients without autotransplantation required calcium supplementation for longer than 1 year. To avoid permanent hypoparathyroidism after TT, it should be essential to preserve at least 2 PGs or to preserve 1 PG and perform autotransplantation.

Parathyroid Autotransplantation During Thyroid Surgery: A Novel Technique Using a Cell Culture Nutrient Solution

INTRODUCTION

Parathyroid autotransplantation is an easy procedure with a low complication rate. We adopted the transplantation into the sternocleidomastoid muscle, which allows an easier and time-saving surgical procedure using the same surgical incision.

METHODS

In this study, we retrospectively reviewed the records of 396 consecutive patients, who underwent total thyroidectomy for benign thyroid disease. In all cases in which a parathyroid was damaged or inadvertently removed, the gland was transplanted; before the autotransplantation, the parathyroid tissue was put in a cell culture nutrient solution for 5 min, afterward fragmented, and then was transplanted in the sternocleidomastoid muscle. To demonstrate a beneficial effect of the cell nutrient solution step, we compared data of transplanted patients with a control group of cases (n = 190) undergoing a standard immediate autotransplantation.

RESULTS

We divided patients in two main groups: group A (n = 160) including subjects that underwent one or more parathyroid gland autotransplantation using the cell nutrient solution, and group B (n = 236) concerning those who were not transplanted. Among patients, 62 hypocalcemias occurred, 40 in the group A and 22 in the group B (P < 0.001): 91.9 % were transient and 8.1 % (5 patients) definitive, all pertaining to the group B. Among controls (group C), 42 hypocalcemias occurred (P = 0.616 vs. group A and P = 0.002 vs. group B) and 3/42 became definitive (P = 0.096 vs. group A and P = 0.121 vs. group B). All differences concerning pre- and postoperative calcium values were statistically significant (P < 0.001).

CONCLUSIONS

We recommend the routine parathyroid autotransplantation, when a vascular damage is certain or suspected, in order to reduce the rate of permanent hypoparathyroidism, using a cell culture nutrient solution before gland transplantation.

Postoperative Hypoparathyroidism and the Viability of the Parathyroid Glands During Thyroidectomy

OBJECTIVES

To prevent hypoparathyroidism after thyroidectomy, preservation of the parathyroid glands and their vascularity are essential. The aim of this study was to determine the association between postoperative parathyroid function and the viability of the parathyroid glands during thyroidectomy.

METHODS

We prospectively analyzed 111 patients who underwent total thyroidectomy and in whom all 4 parathyroid glands were preserved in situ during the operation. The surgeons scored the viability of each parathyroid gland from 0 (normal) to 3 (severely compromised viability) based on its gross appearance and vascularity intraoperatively. The index of parathyroid viability score (IPVS) was defined as the sum of the viability scores of the 4 parathyroid glands. We evaluated the relationship between postoperative parathyroid function and IPVS.

RESULTS

Transient hypoparathyroidism occurred in 25 patients (22.5%), and permanent hypoparathyroidism in 4 patients (3.6%). The IPVS were significantly different in the three groups: 2.87±1.46 in the normal group, 3.68±1.41 in the transient hypoparathyroidism group and 7.50±1.00 in the permanent hypoparathyroidism group. The rates of transient hypoparathyroidism were 13.6% in patients with IPVS 0-2, 23.8% in patients with IPVS 3-4, and 42.9% in patients with IPVS 5-6. All the patients with IPVS of 7 or more had permanent hypoparathyroidism.

CONCLUSION

IPVS is correlated with the incidence of hypoparathyroidism. It could be a good quantitative indicator of the probability of hypoparathyroidism after thyroidectomy.

Parathyroid gland angiography with indocyanine green fluorescence to predict parathyroid function after thyroid surgery

BACKGROUND

Postoperative hypoparathyroidism remains the most common complication following thyroidectomy. The aim of this pilot study was to evaluate the use of intraoperative parathyroid gland angiography in predicting normal parathyroid gland function after thyroid surgery.

METHODS

Angiography with the fluorescent dye indocyanine green (ICG) was performed in patients undergoing total thyroidectomy, to visualize vascularization of identified parathyroid glands.

RESULTS

Some 36 patients underwent ICG angiography during thyroidectomy. All patients received standard calcium and vitamin D supplementation. At least one well vascularized parathyroid gland was demonstrated by ICG angiography in 30 patients. All 30 patients had parathyroid hormone (PTH) levels in the normal range on postoperative day (POD) 1 and 10, and only one patient exhibited asymptomatic hypocalcaemia on POD 1. Mean(s.d.) PTH and calcium levels in these patients were 3·3(1·4) pmol/l and 2·27(0·10) mmol/l respectively on POD 1, and 4·0(1.6) pmol/l and 2·32(0·08) mmol/l on POD 10. Two of the six patients in whom no well vascularized parathyroid gland could be demonstrated developed transient hypoparathyroidism. None of the 36 patients presented symptomatic hypocalcaemia, and none received treatment for hypoparathyroidism.

CONCLUSION

PTH levels on POD 1 were normal in all patients who had at least one well vascularized parathyroid gland demonstrated during surgery by ICG angiography, and none required treatment for hypoparathyroidism.

The risk of hypocalcemia in patients with parathyroid autotransplantation during thyroidectomy

OBJECTIVE

Thyroidectomy is the most common cause of hypocalcemia. Preservation of parathyroid glands in situ is essential in preventing this complication. The aims of our study were to review patients who underwent parathyroid gland autotransplantation during thyroidectomy, and to compare hypocalcemia rates in patients with and without autotransplantation.

MATERIAL AND METHODS

Parathyroid gland autotransplantation was performed in 43 (7.9%) of 543 patients who underwent thyroidectomy between 2008 and 2012.

RESULTS

Forty-four parathyroid glands were autotransplanted in 43 patients, including 36 women and 7 men. The median age was 55 (range: 30 to 68). The most common cause of autotransplantation was vascular comprise of the parathyroid gland. Early postoperative hypocalcemia developed in 37% of patients with autotransplantation, and none developed permanent hypocalcemia. Transient and permanent hypocalcemia rates were 9.6% and 0.4% in patients without autotransplantation, respectively. The risk of transient hypocalcemia was significantly high in patients with parathyroid autotransplantation (p<0.001). There was no difference between the two groups in terms of permanent hypocalcemia (p=0.156).

CONCLUSION

Despite meticulous dissection, parathyroid glands can be devascularized or removed inadvertently during thyroidectomy. Parathyroid autotransplantation is the best method to maintain parathyroid gland function. Although the risk of transient hypocalcemia is increased following parathyroid autotransplantation, long-term results are satisfactory.

The risk of hypocalcemia in patients with parathyroid autotransplantation during thyroidectomy

OBJECTIVE

Thyroidectomy is the most common cause of hypocalcemia. Preservation of parathyroid glands in situ is essential in preventing this complication. The aims of our study were to review patients who underwent parathyroid gland autotransplantation during thyroidectomy, and to compare hypocalcemia rates in patients with and without autotransplantation.

MATERIAL AND METHODS

Parathyroid gland autotransplantation was performed in 43 (7.9%) of 543 patients who underwent thyroidectomy between 2008 and 2012.

RESULTS

Forty-four parathyroid glands were autotransplanted in 43 patients, including 36 women and 7 men. The median age was 55 (range: 30 to 68). The most common cause of autotransplantation was vascular comprise of the parathyroid gland. Early postoperative hypocalcemia developed in 37% of patients with autotransplantation, and none developed permanent hypocalcemia. Transient and permanent hypocalcemia rates were 9.6% and 0.4% in patients without autotransplantation, respectively. The risk of transient hypocalcemia was significantly high in patients with parathyroid autotransplantation (p<0.001). There was no difference between the two groups in terms of permanent hypocalcemia (p=0.156).

CONCLUSION

Despite meticulous dissection, parathyroid glands can be devascularized or removed inadvertently during thyroidectomy. Parathyroid autotransplantation is the best method to maintain parathyroid gland function. Although the risk of transient hypocalcemia is increased following parathyroid autotransplantation, long-term results are satisfactory.

Defining the syndromes of parathyroid failure after total thyroidectomy

Acute and chronic parathyroid insufficiency syndromes are the most common complication after total thyroidectomy. Permanent hypoparathyroidism imposes an important medical burden on patient lifestyle due to the need for lifetime medication, regular visits and significant long-term costs. Its true prevalence has been underestimated due to lack of clear definitions, inadequate follow-up and conflicts of interest when reporting individual patient series. The aim of this review is to propose precise definitions for the different syndromes associated to parathyroid failure based on the follow-up and management of patients developing hypocalcemia (<8 mg/dL at 24 hours) after first-time total thyroidectomy for cancer or goiter at our unit. Short and long-term post-thyroidectomy parathyroid failure presents as three different metabolic syndromes: (I) postoperative hypocalcemia is defined as a s-Ca <8 mg/dL (<2 mmol/L) within 24 hours after surgery requiring calcium/vit D replacement therapy at the time of hospital discharge; (II) protracted hypoparathyroidism as a subnormal iPTH concentration (<13 pg/mL) and/or need for calcium/vit D replacement at 4-6 weeks; and (III) permanent hypoparathyroidism as a subnormal iPTH concentration (<13 pg/mL) and/or need for calcium/vit D replacement 1 year after total thyroidectomy. Each of these syndromes has its own pattern of recovery and should be approached with different therapeutic strategies.

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.

Importance of in situ preservation of parathyroid glands during total thyroidectomy

Background

Parathyroid failure is the most common complication after total thyroidectomy but factors involved are not completely understood. Accidental parathyroidectomy and parathyroid autotransplantation resulting in fewer than four parathyroid glands remaining in situ, and intensity of medical treatment of postoperative hypocalcaemia may have relevant roles. The aim of this study was to determine the relationship between the number of parathyroid glands remaining in situ and parathyroid failure after total thyroidectomy.

Methods

Consecutive patients undergoing first-time total thyroidectomy were studied prospectively, recording the number of Parathyroid Glands Remaining In Situ (PGRIS = 4 − (glands autografted + glands in the specimen)) and the occurrence of postoperative hypocalcaemia, and protracted and permanent hypoparathyroidism. Demographic, disease-related, laboratory and surgical variables were recorded. Patients were classified according to the PGRIS number into group 1–2 (one or two PGRIS), group 3 (three PGRIS) and group 4 (all four glands remaining in situ), and were followed for at least 1 year.

Results

A total of 657 patients were included, 43 in PGRIS group 1–2, 186 in group 3 and 428 in group 4. The prevalence of hypocalcaemia, and of protracted and permanent hypoparathyroidism was inversely related to the PGRIS score (group 1–2: 74, 44 and 16 per cent respectively; group 3: 51·1, 24·7 and 6·5 per cent; group 4: 35·3, 13·1 and 2·6 per cent; P &lt; 0·001). Intact parathyroid hormone concentrations at 24 h and 1 month were inversely correlated with PGRIS score (P &lt; 0·001). Logistic regression identified PGRIS score as the most powerful variable influencing acute and chronic parathyroid failure. In addition, a normal–high serum calcium concentration 1 month after thyroidectomy influenced positively the recovery rate from protracted hypoparathyroidism in all PGRIS categories.

Conclusion

In situ parathyroid preservation is critical in preventing permanent hypoparathyroidism after total thyroidectomy. Active medical treatment of postoperative hypocalcaemia has a positive synergistic effect.

Autotransplantation of Inferior Parathyroid glands during central neck dissection for papillary thyroid carcinoma: a retrospective cohort study

INTRODUCTION

The management of inferior parathyroid glands during central neck dissection (CND) for papillary thyroid carcinoma (PTC) remains controversial. Most surgeons preserve inferior parathyroid glands in situ. Autotransplantation is not routinely performed unless devascularization or inadvertent parathyroidectomy occurs. This retrospective study aimed to compare the incidence of postoperative hypoparathyroidism and central neck lymph node (CNLN) recurrence in patients with PTC who underwent inferior parathyroid glands autotransplantation vs preservation in situ.

METHODS

This is a retrospective study which was conducted in a tertiary referral hospital. A total of 477 patients with PTC (pN1) who underwent total thyroidectomy (TT) and bilateral CND with/without lateral neck dissection were included. Patients' demographical characteristics, tumor stage, incidence of hypoparathyroidism, CNLN recurrence and the number of resected CNLN were analyzed.

RESULTS

Three hundred and twenty-one patients underwent inferior parathyroid glands autotransplantation (autotransplantation group). Inferior parathyroid glands were preserved in situ among 156 patients (preservation group). Permanent hypoparathyroidism rate was 0.9% (3/321) versus 3.8% (6/156) respectively (p = 0.028). Mean numbers of resected CNLN were 15 ± 3 (6-23) (autotransplantation group) versus 11 ± 3 (7-21) (preservation group) (p < 0.001). CNLN recurrence rate was 0.3% (1/321) versus 3.8% (6/156) respectively (p = 0.003).

CONCLUSION

Inferior parathyroid glands autotransplantation during CND of PTC (pN1) might reduce permanent hypoparathyroidism and CNLN recurrence. Further study enrolling more patients with long-term follow-up is needed to support this conclusion.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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 per cent 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).

CONCLUSION

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.