The anatomic basis of parathyroid surgery

Actual role of color-doppler high-resolution neck ultrasonography in primary hyperparathyroidism: a clinical review and an observational study with a comparison of 99mTc-sestamibi parathyroid scintigraphy

PURPOSE

Primary hyperparathyroidism (PHPT) is a frequent endocrine pathology that has surgical treatment as its only decisive measure. High-Resolution Neck Ultrasonography with color-Doppler (CDHR-NUS) and 99mTechnetium-SestaMIBI Parathyroid Scintigraphy (99mTc-MIBI PS) are the two instrumental exams more commonly used in the preoperatory localization of pathologic parathyroids. The aim of this observational study was to outline-in accordance with the latest scientific literature-the precise role of CDHR-NUS in the environment of PHPT, comparing it with that of Parathyroid Scintigraphy.

METHODS

136 patients operated on for PHPT and underwent CDHR-NUS and 99mTc-MIBI PS preoperatively. The CDHR-NUS was carried out by an expert medical sonographer. The results of the two methods were compared between each other and with the results of the operative act for the evaluation of accordance and diagnostic performances.

RESULTS

PHPT is prevalently due to monoglandular pathology (SGD). The parallel use of CDHR-NUS and of 99mTc-MIBI PS does not determine a significant increase in diagnostic accuracy. The preoperative accordance evaluation between the two methods does not exclude the presence of multiglandular pathology (MGD) with certainty.

CONCLUSIONS

CDHR-NUS is an accurate as well as cost-effective method; its role as a main and eventual unique preoperative localization method in patients affected by PHPT is confirmed. In the presence of expert medical sonographers, the sequential use of the two methods is retained correct and their use in parallel is neither justified nor cost-effective. The preoperative accordance evaluation between the two methods is neither necessary nor indispensable.

Prevalence of Thymic Parathyroids in Primary Hyperparathyroidism During Radioguided Parathyroidectomy

Background:

Radioguided surgery has been an effective tool for identifying hyperfunctioning parathyroid glands during routine parathyroidectomy for hyperparathyroidism. The purpose of this study was to examine the role of radioguided surgery for the identification of intrathymic parathyroid glands.

Material and Methods:

Between March 2001 and February 2018, 2291 patients underwent parathyroidectomy by 1 surgeon for primary hyperparathyroidism. Of these patients, 158 (7%) were identified to have an ectopic intrathymic parathyroid gland. All patients underwent radioguided parathyroidectomy. Ex vivo radionuclide counts were used to confirm parathyroid excision with specimen radioactivity of >20% of the background level.

Results:

The mean age was 56 ± 1 years with 74% of the patients being female. Preoperatively, 122 patients underwent sestamibi scan, which correctly identified the affected gland 61% of the time. Mean background radionuclide count was 208 ± 7, mean ex vivo radionuclide count was 127 ± 9, with ex vivo counts of removed glands >20% in all patients. All ectopic parathyroid glands were successfully identified using gamma probe. Ex vivo counts found to be significantly higher in patients with adenomas. Patients with parathyroid adenomas also were older in age and had higher preoperative calcium levels. While 10% of patients with primary hyperparathyroidism have hyperplasia, 42% of patients with thymic parathyroids had hyperplasia.

Conclusions:

Radioguided parathyroidectomy is useful in detecting ectopic parathyroid glands in the thymus. Patients with hyperplasia disproportionately have clinically significant thymic parathyroid glands.

Parathyroid glands: the normal development, anatomy and histological structure

Parathyroid glands (PG) are endocrine glands, which are the most important humoral regulators of calcium and phosphorus metabolism in the body. They were first described by an Englishman Richard Owen in 1849. Most of patients have four PG – upper and lower. In 13% of cases there are more than four PG. The glands arise as diverticula from the endoderm of the third and fourth branchial pouches between the fifth and twelfth week of gestation. The IV branchial pouch forms the upper gland, and III pouch forms the inferior gland. The parathyroid hormone production has been demonstrated as early as 83/7 weeks gestational age. The formation, migration, differentiation and functioning of the PGs are determined by a number of genes and changes in them could lead to disfunction in these processes. The ectopic of PG is possible when migration violation (up to 22% of cases). The most common location of the ectopic PG is parenchyma of the thymus and thyroid gland. Each PG is richly vascularized and it is surrounded by a thin connective tissue. In adults, there are two types of parenchymal cells: the chief cells (active and inactive forms) and the oxyphil cells. During the life, the ratio of types of parenchymal cells and their activity have been changing, as well as the characteristics of the stroma.

The prevalence and anatomy of parathyroid glands: a meta-analysis with implications for parathyroid surgery

Purpose

The anatomy of parathyroid glands (PTG) is highly variable in the population. The aim of this study was to conduct a systematic analysis on the prevalence and location of PTG in healthy and hyperparathyroidism (HPT) patients.

Methods

An extensive search of the major electronic databases was conducted to identify all studies that reported relevant data on the number of PTG per patient and location of PTG. The data was extracted from the eligible studies and pooled into a meta-analysis.

Results

The overall analysis of 26 studies (n = 7005 patients; n = 23,519 PTG) on the number of PTG showed that 81.4% (95% CI 65.4–85.8) of patients have four PTG. A total of 15.9% of PTG are present in ectopic locations, with 11.6% (95% CI 5.1–19.1) in the neck and 4.3% (95% CI 0.7–9.9) in mediastinum. The subgroup analysis of ectopic PTG showed that 51.7% of ectopic PTG in the neck are localized in retroesophageal/paraesophageal space or in the thyroid gland. No significant differences were observed between the healthy and HPT patients and cadaveric and intraoperative studies.

Conclusions

Knowledge regarding the prevalence, location, and anatomy of PTG is essential for surgeons planning for and carrying out parathyroidectomies, as any unidentified PTG, either supernumerary or in ectopic location, can result in unsuccessful treatment and need for reoperation.

Electronic supplementary material

The online version of this article (10.1007/s00423-019-01751-8) contains supplementary material, which is available to authorized users.

Combined ultrasound and Sestamibi scintigraphy provides accurate preoperative localisation for patients with primary hyperparathyroidism

INTRODUCTION

Minimally invasive parathyroidectomy has advantages over the traditional bilateral neck exploration for the surgical treatment of primary hyperparathyroidism. It requires accurate localisation of the parathyroid pathology prior to surgery. The best method of preoperative localisation in a district general hospital setting is not well understood.

METHODS

All patients who underwent parathyroidectomy for primary hyperparathyroidism from 2008 to 2016 were identified from a prospectively maintained database. Operative findings were correlated with radiological and histological results. Sensitivity and specificity of ultrasound, sestamibi scintigraphy and the two together were calculated for diagnostic precision and compared.

RESULTS

One hundred and eighty-four patients met the inclusion criteria, of whom 81.5% had a histological diagnosis of a parathyroid adenoma. Ultrasound had higher sensitivity than sestamibi scintigraphy. Used together, ultrasound and sestamibi scintigraphy performed better than either ultrasound or sestamibi scintigraphy alone (P< 0.001). Twenty-two of 184 cases had no lesion located by either ultrasound or sestamibi scintigraphy preoperatively. Where neither ultrasound nor sestamibi scintigraphy located the lesion, additional computed tomography led to the excision of parathyroid pathology in one in ten patients.

CONCLUSION

The combination of ultrasound and sestamibi scintigraphy provides the highest sensitivity of preoperative localisation. This approach led to a high success rate of minimally invasive parathyroidectomy. Where preoperative localisation is not achieved with ultrasound or sestamibi scintigraphy, computed tomography adds little additional benefit. In this setting other modalities of localisation such a selective venous sampling, intraoperative methylene blue or intraoperative parathyroid hormone levels could be considered.

Ectopic Parathyroid Adenoma in Piriform Sinus: Case Report and Review of the Literature

During routine blood work, a 53-year-old female patient was noted to have asymptomatic hypercalcemia and subsequently found to have hyperparathyroidism. Localization studies for a suspected parathyroid adenoma included ^99mTc Sestamibi scintigraphy, Single Photon Emission Computed Tomography (SPECT)/computed tomography (CT) study, and ultrasound of the neck, which were initially read as negative for parathyroid adenoma. A contrast-enhanced CT scan of the neck was performed to locate the suspected parathyroid adenoma and demonstrated a soft tissue lesion within the right piriform sinus. Flexible fiber optic nasolaryngoscopy revealed a submucosal lesion in the right piriform sinus. Following these findings, the initial ^99mTc Sestamibi scintigraphy and SPECT/CT were reviewed with confirmation of a focal area of increased activity superior to the right thyroid lobe, corresponding to a nodule in the right piriform sinus that demonstrated increased activity on SPECT/CT. The patient was brought to the operating room for surgical management where a laryngoscope and operating microscope were utilized. The encapsulated lesion was dissected and excised in total. The parathyroid hormone and ionized calcium levels normalized postoperatively. Pathology confirmed a parathyroid adenoma. Parathyroid adenomas are the most common cause of primary hyperparathyroidism. Sixteen percent of parathyroid adenomas can be situated in an ectopic location. Ectopic parathyroid adenomas in the piriform sinus are rare with only a few previously documented cases. We document a rare case of ectopic parathyroid adenoma in the piriform sinus overlooked on initial imaging studies. These lesions can be challenging to localize, however, an understanding of embryology, close scrutiny of possible ectopic locations, and the application of complementary imaging techniques may prove useful for surgeons and clinicians.

Targeted Minimally Invasive Parathyroidectomy for Ectopic Aortopulmonary Adenoma Under Gamma Probe Guidance

We report a case of 53-year-old woman with the parathyroid adenoma (PA) located in the aortopulmonary window with an aberrant right subclavian artery. Her preoperative calcium level was 11.3 mg/dL (reference range = 8.8-10.6 mg/dL). The parathyroid hormone level was significantly elevated at 127.4 pg/mL (reference range = 12-88 pg/mL) as measured on immunoradiometric assay. Dual-phase technetium-99m-labeled sestamibi parathyroid scintigraphy and fluorine-18 F-fluorocholine positron emission tomography/computed tomography revealed a mediastinal tumor measuring 3 × 5 × 6 mm located anterolateral to the aortopulmonary window. Minimally invasive removal of PA was performed through 3.5-cm reverse J-shaped partial upper sternotomy to the third intercostal space. Postoperative recovery was uneventful, and serum calcium and parathyroid hormone levels normalized within 24 hours of surgery. Our case represents the rare occurrence of a mediastinal PA associated with aberrant right subclavian artery treated with targeted minimally invasive approach using different imaging modalities including technetium-99m-sestamibi scintigraphy and fluorine-18 F-fluorocholine positron emission tomography/computed tomography, and intraoperative use of gamma probe for precise localization PA.

An Unusual Mass of Posterior Mediastinum: A Case of Retrotracheal Parathyroid Adenoma Presenting With Primary Hyperparathyroidism

Although parathyroid ectopy in the mediastinum has been the subject of several publications, its location in the posterior mediastinum is very rarely reported. We report a case of a 69-year-old patient who presented with clinical symptoms of malignant hypercalcemia due to a retrotracheal mediastinal parathyroid adenoma. The surgical excision leads to a quick normalisation of the phosphocalcic balance with improvement of the clinical symptoms. Ectopic hypersecreting parathyroid adenoma with life-threatening hypercalcemia should prompt radiological assessment and appropriate surgical management to prevent further clinical complications.

High prevalence of chronic kidney disease in patients with multiple endocrine neoplasia type 1 and improved kidney function after parathyroidectomy

BACKGROUND

Because chronic kidney disease is an important comorbidity associated with primary hyperparathyroidism, we sought to evaluate the prevalence of chronic kidney disease and effects of parathyroidectomy on kidney function in patients with multiple endocrine neoplasia type 1-associated primary hyperparathyroidism.

METHODS

We performed a retrospective analysis of 112 patients with multiple endocrine neoplasia type 1-associated primary hyperparathyroidism who had at least 1 operation for primary hyperparathyroidism at 2 tertiary referral centers. The preoperative and postoperative estimated glomerular filtration rates were compared. The prevalence of chronic kidney disease stage 3 or worse (estimated glomerular filtration rates less than 60 mL/min/1.73m²) in this cohort was compared to the rates in the US population reported by the Centers for Disease Control and Prevention.

RESULTS

The median age at the time of parathyroidectomy was 36.5 years (range: 12-76 years). A total of 99 patients had biochemical remission. The rate of chronic kidney disease stage 3 or worse in patients with multiple endocrine neoplasia type 1-associated primary hyperparathyroidism was greater than that observed in the US population for ages 20-39 and 40-59 (5% [n = 2/44] vs 0.39% [n = 18/4565], P = .015 and 10% [n = 4/40] vs 2.31% (n = 89/3848), P = .015, respectively). We observed improved estimated glomerular filtration rates in those with chronic kidney disease stage 3 or worse postoperatively (48 vs 57 mL/min/1.73m², P = .047). A successful parathyroidectomy normalized all 24-hour urine calcium excretion.

CONCLUSION

An indication for early parathyroidectomy should include estimated glomerular filtration rates less than 60mL/min/1.73m² in patients with multiple endocrine neoplasia type 1-associated primary hyperparathyroidism.

Primary Hyperparathyroidism due to Parathyroid Adenoma Originated from Supernumerary Gland

Introduction

The variability of the location of the parathyroid glands is directly related to the events that occur during embryonic development. The impact that an individual submits more than four parathyroid glands is close to 13%. However the presentation of a parathyroid adenoma in a supernumerary gland is an uncommon event.

Case report

A 30-year-old man diagnosed with primary hyperparathyroidism with matching findings on ultrasonography and scintigraphy for parathyroid adenoma localization lower left regarding the thyroid gland. A cervicotomy explorer showed four orthotopic parathyroid glands. The biopsy of the inferior left gland was normal. No signs of adenoma were seen in the biopsy. Following mobilization of the ipsilateral thyroid lobe, fifth parathyroid gland was found increased significantly in size than proceeded to remove, confirming the diagnosis of adenoma. After the excision, the levels of serum calcium and parathyroid hormone were normalized.

Conclusions

The presentation of a parathyroid adenoma in a supernumerary gland is a challenge for the surgeon. The high sensitivity having different imaging techniques has been a key to locate preoperatively the pathological parathyroid gland. Analytical or clinical persistence of primary hyperparathyroidism after parathyroid surgery can occur if the location of the adenoma is a supernumerary or ectopic gland location.

Initial surgical results of 500 Parathyroidectomies for Hyperparathyroidism related to chronic kidney disease - mineral and bone disorder

Introduction:

Surgical treatment of hyperparathyroidism related to chronic kidney disease is a challenging procedure even for experienced parathyroid surgeons. Over the years, adjuvant techniques have been developed to assist the medical team to improve surgical outcomes. However, medical staff in poor countries have less access to these techniques and the effectiveness of surgery in this context is unclear.

Objective:

verify the effectiveness of surgery for treatment of hyperparathyroidism related to chronic kidney disease without adjuvant techniques.

Methods:

Over a 5-years period, patients with hyperparathyroidism that had clinical therapeutic failure were evaluated for surgical treatment. Total parathyroidectomy with autograft or subtotal resection were the selected procedures. Surgeries were performed in a tertiary hospital in Brazil without the assistance of some of the adjuvant techniques that are usually applied, such as frozen section, nerve monitoring, and gamma probe. Intraoperative PTH and localization pre-operative exams were applied, but with huge restrictions.

Results:

A total of 518 patients with hyperparathyroidism (128 secondary and 390 tertiary) were surgically treated. Total parathyroidectomy were performed in 81.5%, subtotal in 12.4%, and 61% of patients had a surgical failure. Of all failures, only 1.4% needed a second surgery totaling 98.6% of successful initial surgical treatment. Neck hematoma and unilateral focal fold paralysis occurred in 1.9% and 1.5%, respectively.

Conclusion:

parathyroidectomy is a safe and reproducible surgical procedure even in the absence of adjuvant techniques.

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.

A garden of parathyroid adenomas

Despite improvements in parathyroidectomy success rates, patients with persistent primary hyperparathyroidism (PHPT) after initial surgery continue to challenge clinicians. Some of the challenges are due to ectopic parathyroid adenomas, including thymic, intrathyroidal, carotid sheath and mediastinal glands, and others are because of supernumerary glands. While uncommon in PHPT, multigland disease is also an important consideration in patients requiring reoperative surgery for persistent disease. For this reason, localisation studies including sestamibi, ultrasound, CT scan and venous sampling for abnormal glands may be an essential component of the preoperative workup. In this report, we describe an unusual case of a patient who required a total of four operations to cure PHPT arising from seven parathyroid adenomas.

Ultrasound detection of normal parathyroid glands: a preliminary study

OBJECTIVE

No previous prospective study has investigated the detection of normal parathyroid glands (PTGs) and their features using real-time ultrasound (US). This study aimed to assess the preoperative US detection of normal PTGs in patients who underwent hemithyroidectomy.

METHODS

Between August and October 2016, 44 patients underwent hemithyroidectomy using a low-collar incision, and 5 were excluded from the study. A single radiologist performed the preoperative US examination in all patients, and the surgical data for the PTGs were obtained by a single surgeon. Based on the surgical findings of PTGs, the preoperative US detection of PTGs was determined.

RESULTS

Of the 39 patients, 3 had no surgical data for PTG (n = 2) and the presence of parathyroid hyperplasia (n = 1). In the 36 remaining patients, in 3 patients, US identification of a normal PTG was corroborated by surgical findings, whereas in 2 patients, US findings differed from surgical findings, and in 31 patients, US did not detect a normal PTG. The successful US detection rate of normal PTG was only 8.3% (3/36).

CONCLUSIONS

US cannot be used for identification of normal PTGs.

Ultrastructure of Hyperfunctioning Parathyroid Glands: Does it Explain Various Patterns of 99mTc-sestamibi Uptake

The aim of this study was to correlate the uptake of ^99mTc-methoxy-isobutyl-isonitrile (MIBI) with ultra-structural features of parathyroid adenomas. Twenty patients with proven primary hyperparathyroidism were evaluated prospectively. Preoperative double-phase ^99mTc-MIBI scintigraphy was performed in all patients and the degree of tracer uptake by the parathyroid lesions was assessed visually and semi-quantitatively. The excised glands were examined histologically and ultrastructurally, and their features were correlated with the degree of the radiotracer uptake. At surgery, 21 parathyroid adenomas were removed (double adenoma in one patient and a solitary adenoma in each of the remaining 19 patients). ^99mTc-MIBI scan detected 18 of the 21 adenomas. There was positive correlation between the degree of ^99mTc-MIBI uptake and the mitochondrial contents of the parathyroid adenoma cells. Four adenomas with intense uptake had high content of mitochondria in the cells. The three false-negative scans had low-to-moderate mitochondrial content. ^99mTc-MIBI uptake is related to the mitochondrial content of the parathyroid adenoma cells.

The Essentials of Parathyroid Hormone Venous Sampling

Hyperparathyroidism is an excess of parathyroid hormone in the blood due to over-activity of one or more parathyroid gland. Localization of abnormal glands with noninvasive imaging modalities, such as technetium sestamibi scan and cross-sectional imaging, has a high success rate. Parathyroid venous sampling is performed for patients with persistent or recurrent disease after previous parathyroid surgery, when repeat noninvasive imaging studies are negative or discordant. The success of invasive localization studies and results interpretation is dependent on the interventional radiologist's understanding of the normal and ectopic anatomic locations of parathyroid glands, as well as their blood supply and venous drainage. Anatomic and technical considerations for selective parathyroid venous sampling are reviewed.

Ectopic parathyroid adenoma in the soft palate: a case report

Background

Ectopic parathyroid adenomas can occur in numerous anatomic locations. While ectopic parathyroid adenomas can rarely occur in the pharyngeal region, this has not previously been described in the soft palate.

Case presentation

We report the first case of ectopic parathyroid adenoma within the soft palate. A 59 year old woman presented with hyperparathyroidism. She remained persistently hyperparathyroid after initial parathyroidectomy. Repeat exploration for a lesion suspicious on PET-CT for an ectopic parathyroid adenoma in the parapharyngeal region was unsuccessful in treating the hyperparathyroidism. An ectopic adenoma in the soft palate was eventually discovered. Removal through a transoral approach was successful in treating the hyperparathyroidism.

Conclusions

Ectopic parathyroid adenomas can occur in various anatomical locations that may be missed even with the use of the various imaging modalities. The soft palate should be added to the list of possible ectopic locations high in the neck.

Hyperparathyroidism — Comparison of Flash Imaging with Spin ECHO MR Imaging

MR images of the neck were prospectively studied in 19 patients with hyperparathyroidism. Fast low angle shot (FLASH) sequence was performed in addition to T1- and T2-weighted spin echo (SE) sequences. FLASH images were obtained with 320/12/20° (TR/TE/flip angle) using presaturation technique. TE of 12 ms was chosen to eliminate high signal of fat tissue. In the evaluation of detectability, a combination of T1-weighted SE and FLASH images (T1WI + FLASH) was compared with a combination of T1- and T2-weighted SE images (T1WI + T2WI). MR imaging correctly depicted 20 of 30 abnormal glands on both T1WI + FLASH and T1WI + T2WI. FLASH imaging effectively eliminated high signal of fat tissue. Nineteen abnormal glands demonstrated higher signal than surrounding tissues on FLASH images, whereas 12 glands were high-intense on T2-weighted SE images. We conclude that FLASH imaging provides improved tissue contrast and anatomic delineation and, thus, may replace T2-weighted SE imaging in the neck.

The differential diagnosis of central compartment radioactive iodine uptake after thyroidectomy: anatomic and surgical considerations

OBJECTIVE

Foci of increased radioactive iodine (RAI) uptake in the thyroid bed following total thyroidectomy (TT) indicate residual thyroid tissue that may be benign or malignant. The use of postoperative RAI therapy in the form of remnant ablation, adjuvant therapy, or therapeutic intervention is often followed by a posttherapy scan. Our objective is to improve the clinician's understanding of the anatomic complexity of this region and to enhance the interpretation of postoperative scans.

METHODS

We conducted a comprehensive review of the literature evaluating RAI uptake in the central compartment following thyroid cancer treatment and literature related to anatomic nuances associated with this region. Thirty-eight articles were selected.

RESULTS

Through extensive surgical experience and a literature review, we identified the 5 most important anatomic considerations for clinicians to understand in the interpretation of foci of increased RAI uptake in the thyroid bed on a diagnostic scan: 1) residual benign thyroid tissue at the level of the posterior thyroid ligament, 2) residual benign thyroid tissue at the superior portion of the pyramidal lobe and/or superior poles of the lateral thyroid lobes, 3) residual benign thyroid tissue that was left attached to a parathyroid gland in order to preserve its vascularity, 4) ectopic benign thyroid tissue, and 5) malignant thyroid tissue that has metastasized to central compartment nodes or invaded visceral structures.

CONCLUSION

By correlating anatomic description, medical illustrations, surgical photos, and scans, we have attempted to clarify the reasons for foci of increased uptake following TT to improve the clinician's understanding of the anatomic complexity of this region.

Intrathyroidal parathyroid adenoma: Diagnostic pitfalls on fine-needle aspiration: Two case reports and literature review

Parathyroid adenomas may occur within the thyroid, clinically simulating thyroid nodules. Fine-needle aspiration (FNA) of these presumably "thyroid nodules" can lead to misinterpretation of cytomorphological findings because of similarities in cytological features of parathyroid and thyroid lesions. Here, we reported two cases of intrathyroidal parathyroid adenomas. One of them was misinterpreted as thyroid lesions. The other was composed exclusively of oncocytic cells and had a correct cytological diagnosis. In this study, both cases showed a new cytological feature which has not been reported in the literature: many capillaries protruding outside the three-dimensional fragments without epithelial cells around. Diagn. Cytopathol. 2016;44:921-925. © 2016 Wiley Periodicals, Inc.

Analysis of the incidence and factors predictive of inadvertent parathyroidectomy during thyroid surgery

BACKGROUND

Inadvertent (or incidental) parathyroidectomy can occur during thyroidectomy. However, the factors associated with inadvertent parathyroidectomy remain unclear. This study aimed to report the rate of inadvertent parathyroidectomy during thyroidectomy and associated risk factors.

METHODS

Variables including fine needle aspiration cytology findings, age, sex, thyroid weight, concurrent neck dissection, extent of thyroidectomy, and the presence of cancer and parathyroid tissue within the specimen were recorded for 266 patients. The incidence of post-operative hypocalcaemia was also recorded. Univariate and multivariate analysis were performed to identify factors associated with inadvertent parathyroidectomy.

RESULTS

The inadvertent parathyroidectomy rate was 16 per cent. Univariate analysis revealed that cancer and concurrent neck dissection predicted inadvertent parathyroidectomy. On multivariate analysis, only concurrent neck dissection remained an independent predictor of inadvertent parathyroidectomy: it was associated with a fourfold increase in inadvertent parathyroidectomy.

CONCLUSION

The inadvertent parathyroidectomy rate was 16 per cent and concurrent neck dissection was identified as an independent predictor of inadvertent parathyroidectomy.

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.

Parathyroid adenoma causing a spontaneous cervical and mediastinal massive hematoma

Cervical and mediastinal hemorrhaging caused by a spontaneous rupture of a parathyroid adenoma has been rarely reported. Herein, we report a case of a 52-year-old woman who experienced a sudden onset of cervical and mediastinal bleeding related to a parathyroid adenoma. The patient had a history of trauma to the left thorax with a fracture of two ribs. Ultrasonography and computer tomography revealed a nodule in the retrotracheal space and hematoma of the bilateral trachea and thorax. Laboratory examinations revealed significant hypercalcemia, hypophosphatemia, and a high level of intact parathyroid hormone. Surgery was performed and a dark-red, soft tumor was found behind the trachea, which adhered to the surrounding tissues. The pathological diagnosis was a parathyroid adenoma with hemosiderin deposition and fibrosis.

Patterns of disease in patients at a tertiary referral centre requiring reoperative parathyroidectomy

INTRODUCTION

Reoperative parathyroidectomy is required when there is persistent or recurrent hyperparathyroidism following the initial surgery (at least 5% of parathyroidectomies nationally). By convention, 'persistent disease' is defined as the situation where the patient has not been cured by the first operation. The term 'recurrent hyperparathyroidism' is used when the patient was confirmed to be biochemically cured for six months from the first operation but has hyperparathyroidism after this date. Reoperative surgery is associated with higher rates of postoperative complications as well as a greater rate of failure to cure. The aim of our study was to review our departmental experience of reoperative parathyroidectomy, with a view to identify patterns of disease persistence and recurrence.

METHODS

Using a departmental database, patients were identified who had undergone reoperative parathyroidectomy between 2006 and 2014. All the pre, intra and postoperative information was documented including the operative note so as to record the location of the abnormal parathyroid gland found at reoperation.

RESULTS

Almost two-thirds (63%) of patients had negative, equivocal or discordant conventional imaging so secondary investigative tools were required frequently. The majority of abnormal glands were found in eutopic locations. The most common locations for ectopic glands were intrathyroidal, mediastinal and intrathymic. A third (33%) of the patients had multigland disease and over a quarter (28%) had coexisting thyroid disease.

CONCLUSIONS

Persistent hyperparathyroidism represents a challenging patient subgroup for which access to all radiological modalities and intraoperative parathyroid hormone monitoring are required. Patient selection for reintervention is a key determinant in the reoperation cure rate.

Liquid-based cytology in the fine needle aspiration of parathyroid lesions: a comparison study with the conventional smear, ThinPrep, and SurePath

Liquid-based cytology (LBC) has been progressively used for evaluating fine needle aspiration (FNA) specimens. However, limited studies have examined LBC in FNA of parathyroid lesions. We retrospectively reviewed 24 FNA specimens of parathyroid lesions, including 6 specimens prepared by conventional smear, 12 specimens prepared using ThinPrep method, and 6 specimens prepared using SurePath method. The 18 LBC specimens were also used for cell block preparation and immunostaining for parathyroid hormone (PTH). LBC specimens more frequently showed variable cellularity; microfollicular structure; bubbly or vacuolated cytoplasm; and small, round cells with distinct borders compared to specimens prepared by conventional smear. ThinPrep specimens showed a clean background and fewer isolated cells and naked nuclei compared to specimens prepared using the other methods. SurePath specimens showed many white blood cells in the background and more scattered single cells and naked nuclei compared to ThinPrep specimens. Specimens prepared using the 3 methods often showed colloid-like material but did not contain dense globular colloidal structures. White blood cells in the background of LBC specimens serve as useful indicators for estimating cell size. The nuclear size of parathyroid cells was similar to or smaller than that of inflammatory cells in the background. Cell block sections showed definite histological features of the parathyroid tissue and strong positive immunostaining for PTH. Awareness of these cytologic features of parathyroid FNA specimens prepared using ThinPrep and SurePath methods may help in preventing misdiagnosis. Cell block preparation and PTH immunostaining should be performed for the definitive diagnosis of parathyroid lesions.

Value of Prophylactic Cervical Thymectomy in Parathyroid Hyperplasia

BACKGROUND

In parathyroid hyperplasia (HPT), parathyroid glands within the cervical thymus are a cause for recurrence. As a result of differences in pathophysiology, variable practice patterns exist regarding performing bilateral cervical thymectomy (BCT) in primary hyperplasia versus hyperplasia from renal failure or familial disease. The objective of this study was to capture patients where thymic tissue was found with subtotal parathyroidectomy (PTX) and intended BCT, identify number of thymic supernumerary glands (SNGs), and determine overall cure rate.

METHODS

Retrospective review of patients with four-gland exploration and intended BCT for HPT from 2000 to 2013 was performed. Identification of thymic tissue and SNGs were determined by operative/pathology reports. Univariate analysis identified differences in cure rate for patients undergoing subtotal PTX with or without BCT.

RESULTS

Thymic tissue was found in 52 % of 328 primary HPT (19 % unilateral, 33 % bilateral), 77 % of 128 renal HPT (28 % unilateral, 49 % bilateral), and 100 % of familial HPT (24 % unilateral, 76 % bilateral) patients. Nine percent of primary, 18 % of renal, and 10 % of familial HPT patients had SNGs within thymectomy specimens. Cure rates of primary HPT patients with BCT were 99 % compared to 94 % in subtotal PTX alone. Renal HPT cure rates were 94 % with BCT compared to 89 % without BCT.

CONCLUSIONS

Renal HPT patients benefited most in cure when thymectomy was performed. Although the rate of SNGs found in primary HPT was lower than renal HPT, the cure rate mimicked the pattern in renal disease. Furthermore, the incidences of SNGs in primary and familial HPT were similar. On the basis of these data, we advocate that BCT be considered in primary HPT when thymic tissue is readily identified.

Undescended parathyroid adenomas as cause of persistent hyperparathyroidism

BACKGROUND

Undescended glands are a rare cause of primary and secondary hyperparathyroidism (HPT), but they are more common, however, among patients with recurrent HPT or those who have undergone a failed initial cervical exploration. The currently development of more precise noninvasive imaging techniques has improved the results of preoperative diagnosis of these ectopic lesions.

METHODS

The operative reports of patients undergoing parathyroidectomy at our institution were reviewed to identify patients with an undescended parathyroid gland adenomas. Demographic, clinical, imaging and surgical variables were recorded.

RESULTS

Three patients were included: 2/598 parathyroidectomies performed for primary HPT and 1/93 performed for secondary HPT. One case is presented as jaw tumor syndrome (JTS). All the patients had undergone at least one operation before the definitive focused surgery and represented 6% of our parathyroid reoperations. No significant complications and no recurrences were observed in the long-term follow up.

CONCLUSIONS

Accurate preoperative localization of these lesions was possible with noninvasive studies. High cure rate is possible through selective approach when accurate preoperative localization. Thorough knowledge of parathyroid embryology and meticulous surgical technique are essential, particularly in patients with previous unsuccessful explorations.

A Retrospective Study of the Impact of Intraoperative Intact Parathyroid Hormone Monitoring During Total Parathyroidectomy for Secondary Hyperparathyroidism: STARD Study

The study aimed to evaluate the diagnostic accuracy of intraoperative intact parathyroid hormone (IO-iPTH) in patients with secondary hyperparathyroidism (HPT). The cut-off for IO-iPTH monitoring remains unknown. This was a single-center retrospective review of 226 consecutive patients (107 males and 119 females) who underwent parathyroidectomy for secondary HPT between May 2010 and March 2014. The predetermined cut-off for IO-iPTH was a 70% IO-iPTH drop from baseline 10 minutes after total parathyroidectomy and thymectomy. We used <60 pg/mL iPTH value on postoperative day 1 (POD1) as an indicator of successful removal of parathyroid glands and reviewed the frequency of reoperation other than in autografted sites during the observation period. This study was based on the Standards for the Reporting of Diagnostic accuracy compliant. The reoperation rate in patients with >60 pg/mL iPTH value (POD1) was significantly higher than that in patients with <60 pg/mL iPTH value (POD1), (13.0% versus 0.5% P = 0.003). Sensitivity, specificity, and accuracy of >70% IO-iPTH drop were 97.5%, 52.2%, and 92.9%, respectively, this criterion was demonstrated to be beneficial in 26 patients. In 5 patients, <70% IO-iPTH drop was observed and further exploration enabled sufficient removal of parathyroid glands. In 21 patients, although fewer than 4 parathyroid glands were removed after enough explorations, >70% IO-iPTH drop enabled termination of operations and iPTH value (POD1) was <60 pg/mL.An iPTH value of <60 pg/mL (POD1) was a good predictor for successful parathyroidectomy. A 70% IO-iPTH drop from the baseline was appropriate to determine sufficient parathyroid gland removal during parathyroidectomy for patients with secondary HPT. [Corrected]

Potential role for carbon nanoparticles identification and preservation in situ of parathyroid glands during total thyroidectomy and central compartment node dissection

OBJECTIVE

To determine the potential role of intraoperative carbon nanoparticles (CN) injections for identification and preservation of parathyroid glands, thereby reducing the postoperative hypocalcaemia.

METHODS

100 patients with thyroid cancer who underwent total thyroidectomy and central compartment node dissection (CCND) were randomly assigned to receive intraoperative injection of (CN) or not for identifying and preserving normal parathyroid glands.

RESULTS

There was no significantly difference for preoperative and postoperative parathyroid hormone (PTH) levels between the CN and control group (P>0.05). The levels of albumin-adjusted serum calcium (AASC) before surgery and at day 1 and 1 month after surgery did not reach the significant difference between the two groups (P>0.05). However, the patients in CN group had the higher level of AASC at day 3 after surgery than those in control group (P=0.044). Transient postoperative hypoparathyroidism occurred in 24 (48%) patients in CN group and 28 (56%) in control groups, respectively (P=0.423). The incidence of transient postoperative hypocalcemia was 20% (10/50) in CN group and 24% (12/50) in control groups, respectively (P=0.629).

CONCLUSIONS

Carbon nanoparticles can make the thyroid gland and the central lymph node black-stained, but no-stained for parathyroid glands. After rapidly identifying parathyroid and distinguishing it from thyroid and lymph nodes by carbon nanoparticles, complete lymph node dissection and preservation of parathyroid glands become feasible during total thyroidectomy with neck lymph node dissection. After identification, strict adherence to capsular dissection remains essential for safe preservation in situ of the parathyroid glands and their blood supply.

MR appearance of parathyroid adenomas at 3 T in patients with primary hyperparathyroidism: what radiologists need to know for pre-operative localization

OBJECTIVES

To identify frequent MRI features of parathyroid adenomas (PTAs) in patients with primary hyperparathyroidism (PHPT) using a fast protocol with a 3 T magnet.

METHODS

Thirty-eight patients with PHPT underwent a 3 T-MR. All patients had positive US and Tc-99 sestamibi, for a total number of 46 PTAs. T2-weighted IDEAL-FSE and T1 IDEAL-sequences, before and after contrast, were performed. Five features of PTAs were recognised: hyperintensity, homogeneous or "marbled" appearance and elongated morphology on T2-sequences; cleavage plane from thyroid gland on T2-outphase; rapid enhancement in post-contrast T1. Image quality for T2-weighted IDEAL FSE and usefulness for IDEAL post-contrast T1-weighted and T2-outphase sequences were also graded.

RESULTS

PTAs were hyperintense in T2-sequences in 44/46 (95.7%), "marbled" in 30/46 (65.2%) and elongated in 38/46 (82.6%) patients. Cleavage plane was observed in 36/46 (78.3%), and rapid enhancement in 20/46 (43.5%) patients. T2-sequences showed both excellent fat suppression and image quality (average scores of 3.2 and 3.1). T2-outphase images demonstrated to be quite useful (score 2.8), whereas, post-contrast T1 images showed a lower degree of utility (score 2.4).

CONCLUSIONS

A fast protocol with 3.0-T MRI, recognising most common features of PTAs, may be used as a second-line method in the preoperative detection of PTAs.

KEY POINTS

3 T MRI protocol based on T2-weighted IDEAL FSE sequences was used. T2-hyperintensity and elongated morphology are common features of PTAs. 3 T MRI could be used in the preoperative detection of PTAs.

Adult perithyroid and cervical thymus-parathyroid unit: case reports of a rare entity

The thymus-parathyroid unit (TPU) occurring in adults is rare.The main symptoms and important clinical findings are as follows: 2 patients presented with neomercazole-resistant Basedow-Graves disease. A third patient presented with thyroid nodules and a fourth patient with a neck mass after thyroid resection for medullary thyroid carcinoma.The main diagnoses were those of thyroid nodules (either in the context of goiter, or not). In the fourth case the diagnosis was of thyroid medullary carcinoma recurrence in the neck. Thyroidectomy was performed in the 2 cases of Basedow-Graves disease and in the third case (wherein selective neck dissection was also performed). In the fourth case, a neck dissection was performed for a possible medullary carcinoma recurrence. A TPU was microscopically detected in 2 cases with perithyroid location, on thyroidectomies for Basedow-Graves disease and in the 2 other cases with neck soft tissue location (associated with thyroid papillary carcinoma and thyroid medullary carcinoma extension). Postsurgical hypocalcemia requiring treatment occurred in both patients with Basedow-Graves disease and in the fourth patient. The presence of TPU should be acknowledged because such lesions can be misdiagnosed as suspect lymph nodes during thyroid surgery for malignant tumors.

Primary hyperparathyroidism due to atypical vertically long cystic adenoma

Parathyroid cystic adenomas are often misdiagnosed as thyroid cysts and routine preoperative diagnostic tools, such as ultrasonography (US) or 99m technetium-sestamibi (99mTc-MIBI) scans, cannot clearly distinguish between these entities. We present a 67-year-old hypercalcemic woman with a cervical cystic lesion who had negative sestamibi scan results. Her laboratory data indicated primary hyperparathyroidism (serum calcium concentration 14.0 mg/dl, phosphate concentration 2.3 mg/dl, and intact parathyroid hormone (PTH) concentration 239 pg/ml). The cervical US and computed tomography scans revealed a large and vertically long cystic mass (12×11×54 mm). A mass was located from the upper end of the left thyroid lobe to the submandibular region and was not clearly distinguishable from the thyroid. For preoperative definitive diagnosis, we carried out a parathyroid fine-needle aspiration (FNA) and PTH assay (PTH–FNA) of liquid aspirated from the cyst. The intact PTH–FNA concentration was 1.28×10⁶ pg/ml, and the patient was diagnosed with primary hyperparathyroidism due to a cystic mass. She underwent a left upper parathyroidectomy and her serum calcium and intact PTH concentration immediately decreased to normal levels. This report describes the usefulness of PTH–FNA for localizing and differentiating an atypical functional parathyroid lesion from nonfunctional tissue in primary hyperparathyroidism.

An analysis of whether surgeon-performed neck ultrasound can be used as the main localizing study in primary hyperparathyroidism

BACKGROUND

Tc-99 sestamibi (MIBI) scan is the imaging study most frequently used in primary hyperparathyroidism (PHP). Transcutaneous cervical ultrasonography (US) is the other modality used for preoperative localization. The aim of this study was to determine whether surgeon-performed neck US can be used as the primary localizing study in PHP.

METHODS

This was a prospective study of 1,000 consecutive patients with first-time, sporadic PHP who underwent parathyroidectomy at a tertiary academic center. All patients had surgeon-performed neck US and MIBI before bilateral neck exploration.

RESULTS

The findings at exploration were 72% single adenoma, 15% double adenoma, and 13% hyperplasia. When US suggested single-gland disease (n = 842), MIBI was concordant in 82.5%, discordant and false in 8%, negative in 7%, and discordant but correct in 2.5%. When US suggested multigland disease (n = 68), MIBI was concordant in 47%, discordant and false in 41%, and negative in 12%. When US was negative (n = 90), MIBI was positive and correct in 43%, negative in 31%, and positive but false in 26%. Surgeon-performed neck US identified unrecognized thyroid nodules in 326 patients (33%), which led to fine-needle aspiration biopsy in 161 (49%) patients and thyroid surgery in 103 (32%) patients, with a final diagnosis of thyroid cancer in 24 (7%) patients.

CONCLUSION

Our results show that MIBI provides additional useful information in only a minority of patients with a positive US in PHP. Nevertheless, MIBI benefits about half of patients with a negative US. Because one-third of this patient population has unrecognized thyroid nodules as well, we propose that the most cost-effective algorithm would be to do US first and reserve MIBI for US-negative cases.

Application of nano-carbon in lymph node dissection for thyroid cancer and protection of parathyroid glands

Background

The aim of this study was to explore a new method to identify and protect parathyroid glands in neck lymph node dissection for patients with thyroid cancer.

Material/Methods

One hundred patients with thyroid cancer underwent total thyroidectomy combined with central neck lymph node dissection. During the operation, 50 patients receiving nano-carbon suspension were included in the experiment group, and 50 patients without nano-carbon suspension were included in the control group. We compared changes in parathyroid hormone levels before surgery and at 48 h after surgery between the 2 groups and of serum Ca²⁺ level within 48 h after surgery, as well as postoperative parathyroid pathological and lymph node dissection results.

Results

Eight and 1 parathyroid glands were detected pathologically in the control and experimental group, respectively. Decrease in parathyroid hormone level at 48 h occurred in 7 patients in the control group and 1 patient in the experimental group. Hypocalcemia was found at 48 h after surgery in 10 patients in the control group and 2 patients in the experimental group.

Conclusions

Nano-carbon suspension can cause development of the thyroid gland and the central lymph node and a negative development of parathyroid glands. Careful identification and removal of black-stained lymphatic tissues in the process of total thyroidectomy with neck lymph node dissection can ensure a complete lymph node dissection and prevent parathyroid damage, thus effectively reducing the incidence of hypoparathyroidism.

Localization of ectopic and supernumerary parathyroid glands in patients with secondary and tertiary hyperparathyroidism: surgical description and correlation with preoperative ultrasonography and Tc99m-Sestamibi scintigraphy

Introdução

O hiperparatireoidismo é uma consequência metabólica esperada na doença renal crônica (DRC). Paratireoides (PT) ectópicas e/ou supranumerárias podem ser causa de falha cirúrgica nos pacientes submetidos à paratireoidectomia total (PTX).

Objetivo

Definir cirurgicamente a localização das PT, em pacientes com hiperparatireoidismo associado à DRC, correlacionar esses achados com os exames pré-operatórios.

Materiais e métodos

Foi conduzido um estudo retrospectivo com 166 pacientes submetidos à PTX. A localização das PT no intraoperatório foi registrada, sendo classificada como tópica ou ectópica. A localização pré-operatória, definida pela ultrassonografia (USG) e pela cintilografia Tc99m-Sestamibi (MIBI), foi comparada com aos achados cirúrgicos.

Resultados

Nos 166 pacientes, foram identificadas 664 PT. Foram classificadas como tópicas e ectópicas 577 (86,4%) e 91(13,6%) glândulas, respectivamente. Oito PT supranumerárias foram encontradas (7 tópicas e 1 ectópica). As localizações mais comuns de PT ectópicas foram as regiões retroesofágica e tímica. Associadas, a USG e a MIBI não identificaram 56 glândulas (61,5%) ectópicas. Entretanto, a MIBI foi positiva para 69,7% daquelas localizadas nas regiões tímicas e mediastinal.

Conclusão

A presença de glândulas ectópicas e supranumerárias em pacientes com hiperparatireoidismo associado à DRC é significativa. Os exames de imagem pré-operatórios não localizaram a maioria das glândulas ectópicas. A MIBI pode ter importância na identificação de PT nas regiões tímica e mediastinal.