Radioguided parathyroidectomy is equally effective for both adenomatous and hyperplastic glands

Patients with normocalcemic versus hypercalcemic hyperparathyroidism: What's really the difference?

INTRODUCTION

Primary hyperparathyroidism (HPT) is typically characterized by elevated parathyroid hormone (PTH) and hypercalcemia; however, some patients develop normocalcemic hyperparathyroidism. Patients with normocalcemic HPT have an elevated PTH with normal calcium levels and no other secondary causes of elevated PTH, and therefore have a unique biochemical profile. The aim of this project is to compare the demographics, presentation, and outcomes for patients with normocalcemic HPT versus patients with hypercalcemic HPT undergoing parathyroidectomy.

METHODS

A single institution, retrospective review was conducted between January 2016 and June 2022. Patients were classified as either having hypercalcemic (calcium >10.4 ​mg/dL) or normocalcemic (calcium ≤10.4 ​mg/dL) HPT. Cure was defined as normal calcium for 6 months post-operatively in the hypercalcemic HPT group and normal PTH (<88 ​pg/mL) for 6 months post-operatively in the normocalcemic HPT group.

RESULTS

Of the 701 patients included in the study, 566 (80.7 ​%) had hypercalcemic HPT and 135 (19.3 ​%) had normocalcemic HPT. The preoperative Ca was 11 ​± ​0.7 ​mg/dL in the hypercalcemic group and 9.8 ​± ​0.4 ​mg/dL in the normocalcemic group (p ​< ​0.001). The preoperative PTH was 148.2 ​± ​180 ​pg/dL in the hypercalcemic group and 117.4 ​± ​105.3 ​pg/dL in the normocalcemic group (p ​= ​0.06). The average age of normocalcemic patients was 56 ​± ​15 years, compared to 59 ​± ​15 years in the hypercalcemic group (p ​= ​0.07). There was no significant difference in sex (p ​= ​0.42). African American patients were more likely to present with hypercalcemic HPT (19.1 ​%) than with normocalcemic HPT (9.6 ​%, p ​= ​0.01). Normocalcemic patients were more likely to report pre-operative symptoms of kidney stones compared to patients with hypercalcemia (53.3 ​% versus 30.4 ​%, p ​< ​0.001). There was no significant difference in pre-operative symptoms of fatigue, bone pain, or fractures. Patients with hypercalcemic HPT were more likely to present with adenoma (64.3 ​%); whereas patients with normocalcemic HPT were more likely to present with hyperplasia (43.3 ​%, p ​< ​0.001). More patients with normocalcemic HPT underwent thymectomy compared to patients with hypercalcemia (39.3 ​% versus 20.8 ​% respectively, p ​< ​0.001). 92.0 ​% of normocalcemic patients achieved cure post-operatively, which was significantly less than in the hypercalcemic group (97.0 ​%, p ​= ​0.02). The 8.0 ​% of normocalcemic patients that did not achieve cure had a mean PTH level of 147.9 ​± ​159 ​pg/mL at 6 months post-operative. Four patients with normocalcemic HPT had recurrence of disease (3 ​%), and three of the four patients underwent bilateral exploration.

CONCLUSIONS

Patients with normocalcemic HPT present with different symptoms compared to patients with hypercalcemic HPT prior to surgery. Additionally, patients with normocalcemic HPT are less likely to achieve cure after surgery, which warrants further investigation.

Radio-guided procedure in minimally invasive surgery for primary hyperparathyroidism

Minimally invasive parathyroidectomy, of choice in most cases of primary hyperparathyroidism, shows a high detection rate, based on precise preoperative localization by MIBI scintigraphy (SPECT/CT) and neck ultrasound. Radioguided minimally invasive parathyroidectomy is an even more effective technique, which shortens surgical times, maintains minimal incision and few complications, allows immediate verification of parathyroid adenoma removal and is especially interesting in patients with ectopic lesions or cervical surgical history. In this paper, the indications, protocols and differences between the two available radioguided parathyroid surgery procedures (MIBI and R.O.L.L.) are exposed.

Vitamin D deficiency is associated with single gland parathyroid disease

BACKGROUND

Primary hyperparathyroidism (PHPT) with low preoperative vitamin D levels is thought to be related to 4-gland hyperplasia. We reviewed final parathyroid pathology in relationship to preoperative vitamin D levels.

METHODS

A retrospective review was performed for all PHPT patients undergoing parathyroidectomy from 2001 to 2019. Patient demographics, laboratory studies, and final pathology were reviewed.

RESULTS

2230 patients were included in the analysis, 78.1% were female with a mean age of 59 years. Patients were stratified into 3 groups based on their preoperative 25-hydroxy vitamin D levels; "deficient" (<20 ng/mL) (n = 319), "insufficient" (20-30 ng/mL) (n = 1108), or "sufficient" (>30 ng/mL) (n = 803). Patients with deficient vitamin D had a higher frequency of single adenoma (71%) compared to sufficient vitamin D patients (62%) (p < 0.001) and fewer hyperplastic glands (19%) compared to sufficient vitamin D level patients (25%) (p < 0.001).

CONCLUSIONS

Vitamin D deficiency is more strongly associated with single-gland parathyroid disease than 4-gland hyperplasia. Further investigation into the complex interplay between vitamin D levels and autonomous parathyroid function is warranted.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Secondary and Tertiary Renal Hyperparathyroidism

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate treatment of secondary (SHPT) and tertiary (THPT) renal hyperparathyroidism.

BACKGROUND

Hyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The surgical management of SHPT and THPT is nuanced and requires a multidisciplinary approach. There are currently no clinical practice guidelines that address the surgical treatment of SHPT and THPT.

METHODS

Medical literature was reviewed from January 1, 1985 to present January 1, 2021 by a panel of 10 experts in SHPT and THPT. Recommendations using the best available evidence was constructed. The American College of Physicians grading system was used to determine levels of evidence. Recommendations were discussed to consensus. The American Association of Endocrine Surgeons membership reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines present the epidemiology and pathophysiology of SHPT and THPT and provide recommendations for work-up and management of SHPT and THPT for all involved clinicians. It outlines the preoperative, intraoperative, and postoperative management of SHPT and THPT, as well as related definitions, operative techniques, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Preoperative and Perioperative Care, Surgical Planning and Parathyroidectomy, Adjuncts and Approaches, Outcomes, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal management of secondary and tertiary renal hyperparathyroidism.

Outpatient parathyroidectomy in the pediatric population: An 18-year experience

BACKGROUND

Parathyroidectomy for primary hyperparathyroidism (pHPT) is safely performed in the outpatient setting in the adult population. However, concern that children and adolescents have higher complication rates and are unable to recognize and communicate symptoms of hypocalcemia has limited same-day discharges in the pediatric population.

METHODS

Nineteen patients aged 8-18 years (14.1 ± 0.7) underwent outpatient parathyroidectomy for pHPT by a single high-volume endocrine surgeon from 2002-2020. Patient demographics, disease, operations, and complications were reviewed.

RESULTS

Sixteen of 19 patients were symptomatic with fatigue (62.5%), joint pain (37.5%) and nephrolithiasis (18.7%) most common. Mean preoperative Ca and PTH were 11.7 ± 0.3 mg/dL and 102.3 ± 11.8pg/mL, respectively. Ten of 19 had a single adenoma and 9 had multigland hyperplasia including one MEN1 and one MEN2A patient. We performed 11 four-gland explorations, 8 unilateral parathyroidectomies; including 9 transcervical thymectomies, 1 total thyroidectomy, and 1 bilateral central neck dissection. Mean 6-month postoperative Ca and PTH levels were 9.5 ± 0.3 mg/dL (range 7.3-10.3) and 29±5.0pg/mL (range 6.3-77), respectively. One patient developed permanent hypoparathyroidism and 1 had temporary hypocalcemia. No temporary or permanent hoarseness, unplanned same-day admission, wound complications, or Emergency Department visits occurred.

CONCLUSION

Outpatient parathyroidectomy can be safely and effectively performed in pediatric patients with primary HPT.

LEVEL OF EVIDENCE

Treatment Study, Level III.

Mediastinal parathyroidectomy: Utilization of a multidisciplinary, robotic-assisted transthoracic approach in challenging cases

BACKGROUND

The majority of ectopic mediastinal parathyroid adenomas are accessible transcervically and those not amenable to this approach pose a significant clinical and technical challenge.

METHODS

Retrospective review of transthoracic robot-assisted mediastinal parathyroidectomy (TTRMP) for primary hyperparathyroidism between 2012 and 2019 at a single institution.

RESULTS

16 patients underwent TTRMP, 63% were female with a mean age of 64 ± 2.0 years. Nine of 16 had prior parathyroidectomy; 80% had persistent disease and a mean 2.8-year delay from index operation until TTRMP. Locations included: intrathymic (8), AP window (4), carina (3), and retroesophageal (1). Two patients underwent parathyroid reimplantation. Mean post-operative calcium and PTH were 9.2 ± 0.2 mg/dL and 20.2 ± 5.6 pg/mL, respectively. Complications included: temporary hypocalcemia (4), permanent hypocalcemia (1), DVT (1), hoarseness (1), and subcostal neuralgia (1).

CONCLUSION

In experienced hands, TTRMP is a safe and effective approach to mediastinal parathyroids not accessible transcervically. A multidisciplinary approach should be used in reoperative cases.

Radioguided surgery in primary hyperparathyroidism: a review of the different available techniques

Parathyroidectomy has evolved over the years from bilateral neck exploration to a single gland approach using minimally invasive surgery. The precise presurgical localization of the problem gland, using functional techniques, such as double-phase scintigraphy with [^99mTc] Tc-MIBI including SPECT-CT and PET-CT with [¹⁸F]-Choline and morphological ones, such as ultrasound have played a crucial role in this paradigm's shift. Radioguided surgery techniques have also adapted and grown with new contributions known for their indication in other fields. Thus, we currently have a wide range of techniques that have been added to the minimally invasive radioguided parathyroidectomy with [^99mTc] Tc-MIBI, which was the first on the stage and for which more experience exists. Among them, in this update, we will discuss parathyroidectomy using ultrasound-guided ROLL technique as well as with the use of ¹²⁵I seeds and finally, hybrid techniques that use radiotracer and fluorescence.

Persistent Elevation of Parathormone Levels after Surgery for Primary Hyperparathyroidism

BACKGROUND

Persistent elevation of serum parathyroid hormone (PTH) despite normocalcemia have been documented in 8- 40% of patients after parathyroidectomy. We hereby report our experience from different centers across India to determine clinical significance of postoperatively elevated PTH levels and review relevant literature.

METHODS

We conducted a retrospective case series study and reviewed all the patients who underwent surgery for primary hyperparathyroidism (PHPT) from April 2010 to January 2020.

RESULTS

Total of 201 patients was diagnosed as PHPT. Out of available follow-up data of 180 patients, a total of 54 patients (30%) had persistently elevated PTH (PePTH) at 1 month. Patients with PePTH were older with higher preoperative serum calcium, iPTH, alkaline phosphatase and lower serum phosphate and 25-hydroxy vitamin D3 levels. Creatinine clearance was found to be significantly lower in patients with PePTH. Multiple linear regression analysis revealed that preoperative 25-OH D3 concentration, creatinine clearance and iPTH are the factors influencing persistent elevation of PTH levels. Significantly lower serum calcium and higher alkaline phosphatase levels were observed in PePTH patients with preoperative 25-OH D3 levels <20 ng/mL. Thirty patients at 6 months, 24 patients at 1 year, 18 patients at 2 years and 9 patients at 3 years had eucalcemic PTH elevation. Nine out of 126 (7%) patients with normal initial postoperative calcium and iPTH levels developed PePTH, with none culminating into recurrent hyperparathyroidism.

CONCLUSION

Though the pathogenesis of such a phenomenon still remains to be elucidated, a multifactorial mechanism appears to play a role.

Intraoperative Adjunct Methods for Localization in Primary Hyperparathyroidism

Primary hyperparathyroidism (pHPT) is a frequently seen endocrine disease, and its main treatment is surgery. In the majority of pHPT, the disease involves only a single gland, and the majority of the pathological glands can be determined by preoperative localization methods.In addition to preoperative localization studies in parathyroidectomy, the use of adjunct methods to improve intraoperative localization in order to increase success of surgery is becoming widespread. These methods include different approaches, mainly intraoperative parathyroid hormone (PTH) measurement, followed by intraoperative gamma probe application, intraoperative ultrasonography, parathyroid imaging with methylene blue, and frozen section examination. Recently, especially promising new imaging methods have been described in the literature with various optical technologies to increase the localization of the parathyroid glands and to evaluate their viability. These methods include parathyroid imaging with autofluorescence, indocyanine green imaging with autofluorescence, autofluorescence imaging with methylene blue, autofluorescence imaging with 5-aminolevulinic acid, optical coherence tomography, laser speckle contrast imaging, dynamic optical contrast imaging, and Raman spectroscopy. Currently, minimally invasive parathyroidectomy has become the standard treatment for selected pHPT patients with the aid of preoperative imaging and intraoperative auxiliary methods . The aim of the present study was to evaluate the routinely used new promising intraoperative adjunct methods in pHPT.

Preventing blind thyroid lobectomy in patients with intrathyroidal hyperfunctioning parathyroid glands with radioguided enucleation

Aim: Hyperfunctioning intrathyroidal parathyroid glands are rare and often result in thyroid lobectomy. This study examines the utility of radioguided surgery to guide enucleation of intrathyroidal parathyroids. Methods: Between December 2002 and March 2018, 2291 patients underwent parathyroidectomy by one surgeon for primary hyperparathyroidism. A total of 74 (3%) patients had an ectopic intrathyroidal parathyroid gland and underwent radioguided. Results: All of intrathyroidal parathyroid glands were localized with the gamma probe. In vivo radionuclide counts were above 120% of the background in all but three patients. All intrathyroidal parathyroids were enucleated with the guidance of the gamma probe. Conclusion: Radioguided surgery is useful for intraoperative identification of hyperfunctioning, intrathyroidal parathyroid glands. This technique allows for enucleation of the abnormal parathyroid gland, avoiding thyroid lobectomy and preserving healthy thyroid parenchyma.

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.

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.

The history of the parathyroid surgery

The authors conducted a review of the major aspects of progression of knowledge about the surgical treatment of hyperparathyroidism. Through literature review, we analyzed articles on the history of the evolution of anatomical, physiological, pathological and surgical knowledge of the parathyroid glands. Because of their unique anatomical features, the parathyroid glands were the last of the endocrine glands to be discovered, which greatly hindered proper treatment until the first decades of the twentieth century. Technological developments in the last 30 years greatly facilitated the location of the glands and hyperparathyroidism surgery. However, an experienced and dedicated surgeon is still essential to the excellence of treatment. RESUMO Os autores fizeram uma revisão dos principais aspectos históricos da progressão do conhecimento sobre o tratamento cirúrgico do hiperparatireoidismo. Por meio de revisão bibliográfica, foram analisados artigos selecionados sobre a história da evolução do conhecimento anatômico, fisiológico, patológico e cirúrgico das glândulas paratireoides. Devido às suas características anatômicas peculiares, as paratireoides foram as últimas das glândulas endócrinas a serem descobertas, o que dificultou sobremaneira seu tratamento adequado até as primeiras décadas do Século XX. A evolução tecnológica ocorrida nos últimos 30 anos facilitou sobremaneira a localização das glândulas e a cirurgia do hiperparatireoidismo. Contudo, um cirurgião experiente e dedicado ao tratamento dessa enfermidade ainda é fundamental para a excelência do tratamento.

Update in Parathyroid Imaging

Primary hyperparathyroidism (PHPT) is characterized by excessive, dysregulated production of parathyroid hormone (PTH) by 1 or more abnormal parathyroid glands. Minimally invasive surgical techniques have created a need for more precise localization of the parathyroid lesion by imaging. A variety of imaging protocols and techniques have been used for this purpose, but no one modality is clearly superior. Nuclear medicine scintigraphy and ultrasound imaging are established modalities, although multiphase or 4-dimensional computed tomography is an emerging modality with several advantages. This review provides a background regarding PHPT and key anatomy, and discusses these alternative parathyroid imaging modalities with updates.

The Sestamibi Paradox: Improving Intraoperative Localization of Parathyroid Adenomas

Accurate localization of parathyroid adenomas allows for minimally invasive parathyroidectomy. This results in a shorter length of stay and increased patient satisfaction. Preoperative Technetium (99mTc) sestamibi scans accurately localize parathyroid adenomas in 70 to 85 per cent of cases. If a patient has a negative scan, it is logical to believe that with a preoperative sestamibi injection, the gamma probe may fail to help find an adenoma. We hypothesized that the gamma probe would not be useful intraoperatively for patients with primary hyperparathyroidism (PHPTH) and a negative sestamibi scan. We retrospectively reviewed the cases of parathyroidectomy at our institution from 2010 to 2016. We selected patients with PHPTH and negative sestamibi scan. In all cases, an attempt was made to find adenomas intraoperatively with the gamma probe. A frozen section was obtained as well as intraoperative parathyroid hormone levels to confirm removal of hyperfunctioning parathyroid tissue. There were 132 parathyroidectomies of which 22 had PHPTH and a negative sestamibi scan. One case was excluded because of insufficient documentation of the intraoperative use of the gamma probe. In 19 of the 21 patients analyzed, the gamma probe successfully identified the adenoma in the operating room (sensitivity, 90.5%). In two patients, the gamma probe did not aid in localization. There were no false positives. In all cases, the parathyroid resected was confirmed by frozen section. The intraoperative parathyroid hormone levels dropped >50 per cent in all but three cases, two of which corresponded to those cases where the gamma probe did not help. Even in patients with negative sestamibi scans, intraoperative use of the gamma probe after preoperative sestamibi injection is effective in localizing parathyroid adenomas.

Association of Parathyroid Gland Biopsy Excision Technique With Ex Vivo Radiation Counts During Radioguided Parathyroid Surgery

Importance

Parathyroid biopsy represents a means for normal and hyperfunctional glands to be distinguished intraoperatively. However, no data exist to guide surgeons regarding how much of a parathyroid gland must be biopsied to satisfy the 20% rule.

Objective

To quantify the relative proportion of a hyperfunctional parathyroid gland that must be evaluated with the gamma probe to satisfy the 20% rule.

Design, Setting, and Participants

A retrospective review of surgical data for 24 consecutive patients (16 women, 18 men; mean [SD] age, 66.6 [10] years; range, 51-83 years) who underwent surgery for primary hyperparathyroidism between May and October, 2015, in a tertieary academic medical center.

Main Outcomes and Measures

Extirpated parathyroid glands were sectioned into parallel or pie-shaped biopsies and evaluated ex vivo with a gamma probe to determine what percentage of a hyperfunctional gland must be sampled to meet the Norman 20% rule. The hypothesis was formulated during data collection.

Results

In total, 253 ex vivo biopsy specimens were obtained from 33 surgically removed parathyroid glands. Parathyroid biopsies satisfied the 20% rule with an accuracy that depended on the relative proportion of the parent gland represented: half or more (96.6%; 95% CI, 91.7%-100.0%), a quarter to one-half (87.0%; 95% CI, 79.3%-94.7%), less than a quarter (63.6%; 95% CI, 54.5%-72.8%). When less than a quarter of the gland was removed, pie-shaped biopsies were more likely to satisfy the 20% rule compared with parallel biopsies of the same weight (78.4% vs 56.2%; absolute difference, 22.2%; 95% CI, 4.7%-39.7%).

Conclusions and Relevance

Unless half of a parathyroid gland is biopsied during radioguided parathyroidectomy, the 20% rule cannot reliably rule out the presence of a hyperfunctional parathyroid lesion. Pie-shaped biopsies originating from the center of the gland are associated with a lower rate of false-negative results compared with peripheral biopsies of similar size. Pie-shaped biopsies and biopsy of half or more of each nonexcised parathyroid gland for ex vivo counts may increase the risk of remnant devascularization and resultant hypoparathyroidism.

Minimally Invasive Parathyroidectomy Versus Bilateral Neck Exploration for Primary Hyperparathyroidism

Primary hyperparathyroidism is a disease that is caused by excess parathyroid hormone (PTH) secretion from 1 or more of the parathyroid glands. Surgery is the only cure. Traditional surgical management consists of a 4-gland cervical exploration. Development of imaging specific to identification of parathyroid glands and application of the rapid PTH assay to operative management have made more minimal exploration possible. There are distinct advantages and disadvantages of minimally invasive parathyroidectomy (MIP) and bilateral neck exploration (BNE). The advantages of MIP seem to outweigh those of BNE, and MIP has replaced BNE as the operation of choice by many surgeons.

Use of the gamma probe to identify multigland disease in primary hyperparathyroidism

AIM

The purpose of this study was to determine threshold gamma probe counts to distinguish single adenoma (SA) from multigland disease (MGD) during radioguided parathyroidectomy.

METHODS

A retrospective analysis of 1656 patients was performed. Ex vivo counts of the first excised gland were taken and recorded as a percentage of background counts.

RESULTS

69.4% of MGD patients had counts below the 50% threshold. The 50% threshold correctly grouped 72.8% of our cohort. Counts of more than 100% were accurate for grouping SA, with only 6.8% of patients with counts more than 100% having MGD.

CONCLUSIONS

The gamma probe can aid surgeons in deciding to continue neck exploration if MGD is suspected or wait for labs to confirm cure if SA is suspected.

Primary hyperparathyroidism

Primary hyperparathyroidism is a common endocrine disorder caused by overactivation of parathyroid glands resulting in excessive release of parathyroid hormone. The resultant hypercalcemia leads to a myriad of symptoms. Primary hyperparathyroidism may increase a patient's morbidity and even mortality if left untreated. During the last few decades, disease presentation has shifted from the classic presentation of severe bone and kidney manifestations to most patients now being diagnosed on routine labs. Although surgery is the only curative therapy, many advances have been made over the past decades in the diagnosis and the surgical management of primary hyperparathyroidism. The aim of this review is to summarize the characteristics of the disease, the work up, and the treatment options.

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.

Backscattering intensity measurements in optical coherence tomography as a method to identify parathyroid glands

BACKGROUND AND OBJECTIVE

Previous studies have shown that the use of optical coherence tomography (OCT) permits the differentiation between parathyroid tissue, thyroid tissue, lymph nodes and adipose tissue. We investigated the backscattering intensity profiles of OCT images in order to determine whether significant differences between these tissue types exist.

METHODS

Mean backscattering intensity profiles were obtained from OCT images of parathyroid glands, thyroid tissue, lymph nodes and adipose tissue. The profiles were analyzed employing Fisher's Linear Discriminant Analysis (LDA). The results were cross validated employing improved parameter estimation techniques.

RESULTS

Mean backscattering intensity profiles from 300 OCT images of 34 patients undergoing thyroid or parathyroid surgery were analyzed. The overall rate of correct classifications was 96.15%. The cross validation employing improved parameter estimation techniques yielded results identical to those derived from Fisher's LDA.

CONCLUSION

Besides the individual assessment of OCT images by interpreting morphological criteria, backscattering intensity measurements can reliably distinguish between different tissue entities.

Radioguided parathyroidectomy for tertiary hyperparathyroidism

BACKGROUND

Tertiary hyperparathyroidism (3HPT) is defined as the persistent hyperproduction of parathyroid hormone and resulting hypercalcemia after renal transplantation. Here, we examine the utility of radioguided parathyroidectomy (RGP) in patients with 3HPT.

MATERIALS AND METHODS

We reviewed a prospective surgery database containing 80 3HPT patients who underwent RGP from January 2001-July 2014 at our institution. We evaluated patient demographics, operative management, radioguided neoprobe utilization, and operative outcomes. Data are reported as mean ± standard error of the mean.

RESULTS

The mean age of the patients was 52 ± 1 y, and 46% were male. A total of 69 patients had hyperplasia and received subtotal parathyroidectomy, whereas 5 patients had double adenomas and 6 patients had single adenomas. The average calcium level among 3HPT patients was 10.8 ± 0.1 mg/dL preoperatively and 8.7 ± 0.1 mg/dL postoperatively. In vivo radioguided counts normalized to background counts averaged 145 ± 4%, whereas ex vivo counts normalized to background counts averaged 69 ± 5%. All but one ex vivo count was >20%. Ectopically located glands were successfully localized in 38 patients using the gamma probe. Ex vivo percentage did not correlate with parathyroid gland weight, preoperative parathyroid hormone, or preoperative calcium. Our radioguided approach achieved normocalcemia in 96% of 3HPT patients undergoing RGP; two patients developed recurrent disease.

CONCLUSIONS

In this series, all enlarged parathyroid glands were localized and resected using the gamma probe. Thus, RGP reliably localizes adenomatous, hyperplastic, and ectopically located glands in patients with 3HPT, resulting in high cure rate after resection.

Intraoperative optical coherence tomography imaging to identify parathyroid glands

OBJECTIVE

Optical coherence tomography (OCT) is a non-invasive high-resolution imaging technique that permits characterization of microarchitectural features in real time. Previous ex vivo studies have shown that the technique is capable of distinguishing between parathyroid tissue, thyroid tissue, lymph nodes, and adipose tissue. The purpose of this study was to evaluate the practicality of OCT during open and minimally invasive parathyroid and thyroid surgery.

METHODS

During parathyroid and thyroid surgery, OCT images were generated from parathyroid glands, thyroid tissue, lymph nodes, and adipose tissue. The images were immediately assessed by the operating team using the previously defined criteria. Second, the OCT images were blinded with respect to their origin and analyzed by two investigators. Whenever possible the OCT findings were matched to the corresponding histology.

RESULTS

A total of 227 OCT images from 27 patients undergoing open or minimally invasive thyroid or parathyroid surgery were analyzed. Parathyroid glands were correctly identified in 69.2%, thyroid tissue in 74.5%, lymph nodes in 37.5%, and adipose tissue in 69.2%. 43 OCT images (18.9%) could not be allocated to one of the tissue types (Table 2). Sensitivity and specificity in distinguishing parathyroid tissue from the other entities were 69% (63 true positive, 13 false negative findings, 15 images where an allocation was not possible) and 66%, respectively (71 true negative, 9 false positive, 28 images where an assessment was not possible).

CONCLUSION

OCT is capable of distinguishing between parathyroid, thyroid, and adipose tissue. An accurate differentiation between parathyroid tissue and lymph nodes was not possible. The disappointing results compared to the previous ex vivo study are related to problems handling the endoscopic probe intraoperatively. However, further refinement of this new technology may lead to OCT systems with higher resolution and intraoperative probes that are easier to handle.

Intraoperative parathyroid hormone monitoring corroborates the success of parathyroidectomy in children

OBJECTIVE

To assess the efficacy of intraoperative parathyroid hormone (PTH) monitoring in evaluating the outcome of parathyroidectomy in pediatric patients.

METHODS

Intraoperative PTH monitoring during parathyroidectomy was performed in five children (3M, 2F); three had parathyroid adenomas (single gland disease) and two had primary hyperplasia. One patient had undergone two previous surgical interventions to remove the parathyroid glands, but the PTH levels had remained high with persistence of symptoms. Immunoradiometric analysis was used for PTH measurements. Preoperative PTH values were obtained to monitor the baseline levels. Serum samples were collected 20 minutes after removal of the adenoma/parathyroid gland(s) and PTH levels were compared with preoperative values. Specimens were also confirmed by frozen sectional examination.

RESULTS

Mean age of the patients was 11 years (range: 3 months-16 years). Mean preoperative PTH values were 633.3±579 pg/mL (range: 143-1300 pg/mL). Intraoperative values decreased to 18.7±5.5 pg/mL (range: 8-27 pg/mL) following removal of the gland(s). Normal calcium levels were achieved with adequate management following surgery. One patient (with multiple surgeries and found to have an ectopic parathyroid gland) had hungry bone syndrome after the operation and was treated successfully. There were no major complications. All patients maintained normal calcium/phosphorus levels in the follow-up period, ranging from 2 to 5 years.

CONCLUSION

An ectopic parathyroid gland or another undetected adenoma can be overlooked during surgery. Owing to the short life of the hormone, intraoperative PTH monitoring to determine PTH clearance proved to be a feasible marker for adequacy and safety of surgery and "cure".

Minimally invasive video-assisted parathyroidectomy without intraoperative parathyroid hormone monitoring

INTRODUCTION AND OBJECTIVES

surgical treatment of primary hyperparathyroidism has evolved from the classical bilateral neck exploration to minimally invasive techniques due to recent advances in preoperative localisation methods. The additional value of intraoperative parathyroid hormone (PTH) monitoring is questioned. The aim of this study was to analyse the results of minimally invasive video-assisted parathyroidectomy (MIVAP) without intraoperative PTH monitoring.

METHODS

the patients who underwent MIVAP without PTH monitoring for primary hyperparathyroidism between 2007 and 2013 were evaluated. In all cases the suspected enlarged gland was identified preoperatively by 99Tc-sestamibi scintigraphy, ultrasound or computed tomography.

RESULTS

71 patients were studied (56 females and 15 males), with a mean age of 60 years. In 3 cases (4%) the technique was converted to open parathyroidectomy. Calcium and PTH levels were normalised after first surgery in 69 cases (97%), and after a second surgery in the remaining 2 cases (a second contralateral and a second intrathyroid adenoma). One patient developed a postoperative wound infection, 1 postoperative hypocalcaemia, and 4 transient vocal fold paralysis. No permanent vocal fold paralysis or other complications were observed.

CONCLUSIONS

MIVAP is a safe, effective surgical technique to cure primary hyperparathyroidism. Intraoperative PTH monitoring may not be routinely necessary in patients treated with this technique.

Primary hyperparathyroidism across the ages: presentation and outcomes

BACKGROUND

Primary hyperparathyroidism (PHPT) is a disease process traditionally thought to present during middle age, but can occur at any age. The purpose of this study was to compare PHPT patient characteristics based on patient age at the time of surgical referral.

METHODS

A retrospective review of a prospectively managed database of adult patients undergoing parathyroid surgery for PHPT was conducted. Patients with a negative family history, no previous parathyroid surgery, and ≥6-mo follow-up were included. Patients were grouped by age for comparison.

RESULTS

From 2001-2012, 1372 patients met inclusion criteria. Age groups were as follows: ≤50 y, 51-60 y, 61-70 y, and >70 y. Female predominance increased with age (P>0.01). Baseline serum parathyroid hormone levels were higher at the extremes of age (P<0.001). Young patients had the highest serum calcium (P<0.01), urinary calcium (P<0.001), and T-score (P<0.001) measures, and greater incidence of vitamin D deficiency (P=0.03). The use of local anesthesia increased with age, whereas use of outpatient parathyroidectomy decreased with age (both P<0.01). Rates of disease persistence (2.3%-2.9%, P=0.95) and recurrence (2.1%-3.3%, P=0.75) were low, and did not differ.

CONCLUSIONS

Patients at the extremes of age are referred with more elevated laboratory indices whereas those in the traditional age range have milder biochemical indices. This may result from differential surgical referral. Individuals with laboratory evidence of abnormal calcium and parathyroid hormone regulation should be evaluated for parathyroidectomy regardless of age because all ages can be successfully treated.

The efficacy of low and high dose (99m)Tc-MIBI protocols for intraoperative identification of hyperplastic parathyroid glands in secondary hyperparathyroidism

OBJECTIVE

The aim of this study was to compare the efficacy of low- and high-dose (99m)Tc-MIBI protocols for intraoperative identification of hyperplastic parathyroid glands via gamma probe in secondary hyperparathyroidism.

MATERIAL AND METHODS

This retrospective study was conducted using a prospective database of 59 patients who had undergone radioguided subtotal parathyroidectomy between 2004-2012. The patients were studied in 2 groups. Group 1 (n=31) received 37 MBq (99m)Tc-MIBI intravenously in the surgical room approximately 10 min before the beginning of the intervention and surgery was performed under gamma probe guidance. Group 2 (n=28) received 555 MBq (99m)Tc- MIBI intravenously 2h before surgery, which was also performed under gamma probe guidance. Intraoperative gamma probe findings, laboratory findings, and histopathological findings were evaluated together.

RESULTS

Using acceptance of the histopathological findings as gold standard, sensitivity and specificity of intraoperative gamma probe for identifying hyperplastic parathyroid glands was 98% and 100%, respectively, in both groups.

CONCLUSIONS

In the light of these findings, it is concluded that the low-dose (99m)Tc-MIBI protocol might be preferable for intraoperative identification of hyperplastic parathyroid glands in secondary hyperparathyroidism patients because it was observed to be as effective as the high-dose (99m)Tc-MIBI protocol. Furthermore, the low-dose protocol does not have the disadvantages that are associated with the high-dose protocol.

Parathyroid carcinoma

Parathyroid carcinoma is a rare form of endocrine malignancy accounting for only a small minority of cancer cases. Due to the rarity of this cancer, there are no generalized guidelines for its management; however, surgery remains to be the mainstay therapy. The purpose of this article is to review and summarize the available literature on parathyroid carcinoma, while discussing proposed staging systems and the role of available adjuvant therapies.

Predictors of recurrence in primary hyperparathyroidism: an analysis of 1386 cases

OBJECTIVE

The purpose of this study was to determine whether the operative approach independently influenced recurrence and to identify perioperative predictors of recurrence.

BACKGROUND

Intraoperative parathyroid hormone (IoPTH) monitoring has enabled surgeons to perform minimally invasive parathyroidectomy (MIP). Yet, the long-term durability of this approach has recently been questioned.

STUDY DESIGN

A retrospective review was performed, and cases of initial neck surgery for nonfamilial primary hyperparathyroidism were selected for analysis. Cases were classified as either open parathyroidectomy (OP) when both sides of the neck were explored or MIP when only one side was explored. Kaplan-Meier estimates were plotted for disease-free survival, and a Cox proportional hazards model was developed to evaluate factors associated with recurrence for both the entire cohort and the MIP subset. Further comparisons were made between those who recurred and those who did not recur.

RESULTS

In the past 10-year period, 1368 parathyroid operations for primary hyperparathyroidism were performed at our institution. A total of 1006 were MIP whereas 380 were OP. There were no differences in recurrence between the MIP and OP groups (2.5% vs 2.1%; P = 0.68), and the operative approach (MIP vs OP) did not independently predict recurrent disease in our multivariate analysis. The percentage decrease in IoPTH was protective against recurrence for both the entire cohort (hazard ratio = 0.96; 95% confidence interval = 0.93-0.99; P = 0.03) and the MIP subset. A higher postoperative PTH also independently predicted disease recurrence.

CONCLUSIONS

Operative approach does not independently predict recurrent hyperparathyroidism. The percentage decrease in IoPTH is one of many adjuncts the surgeon can use to determine which patients are best served by bilateral exploration whereas the postoperative PTH can guide follow-up after parathyroidectomy.

Optical coherence tomography as a method to identify parathyroid glands

BACKGROUND AND OBJECTIVE

The identification of parathyroid glands can be a major problem in parathyroid surgery. The purpose of this study was to evaluate the feasibility of optical coherence tomography (OCT) in distinguishing between parathyroid tissue, thyroid tissue, lymph nodes, and adipose tissue.

METHODS

Ex vivo OCT images as well as histological sections were generated from parathyroid glands, thyroid tissue, lymph nodes and fat in order to define significant morphologic differences between these entities. As a second step all OCT images were separately evaluated by two blinded investigators and later compared to the corresponding histology. Sensitivity and specificity of OCT in distinguishing between the different tissues were determined. To assess the interobserver agreement, κ coefficients were calculated from the ratings of each investigator for each OCT image seen.

RESULTS

A total of 320 OCT images from 32 patients undergoing thyroid surgery, parathyroidectomy or lymphadenectomy were compared with the corresponding histology. The sensitivity and specificity in distinguishing parathyroid tissue from the other entities was 84% (second investigator: 82%) and 94% (93%) respectively. Unweighted κ using four diagnostic categories was 0.97 (95% CI, 0.94-0.99) showing substantial agreement between both investigators.

CONCLUSION

OCT is highly sensitive in distinguishing between parathyroid tissue, thyroid tissue, lymph nodes and adipose tissue. These ex vivo results should be confirmed by using OCT imaging intraoperatively.

Multigland disease and slower decline in intraoperative PTH characterize mild primary hyperparathyroidism

BACKGROUND

Many patients with primary hyperparathyroidism (PHPT) present with less severe biochemical parameters. The purpose of this study was to compare the presentation, operative findings, and outcomes of these patients with "mild" PHPT to patients with "overt" disease.

METHODS

A retrospective review of a prospectively collected parathyroid database was performed to identify cases of PHPT undergoing an initial neck operation. Patients were classified as mild when either the preoperative calcium or PTH was within the normal limits. Comparisons were made with the Student's t test, Chi-squared test, or Wilcoxon rank-sum test where appropriate. Kaplan-Meier estimates were plotted for disease-free survival and compared by the log-rank test.

RESULTS

Of the 1,429 patients who met inclusion criteria, 1,049 were classified as overt and 388 (27.1 %) were mild. Within the mild group, 122 (31.4 %) presented with normocalcemic PHPT and 266 (68.6 %) had a normal PTH. The two groups had similar demographics and renal function. Interestingly, the mild group had more than double the rate of kidney stones (3.1 vs. 1.3 %, p = 0.02). The mild group was less likely to localize on sestamibi scan (62.4 vs. 78.7 %, p < 0.01). Intraoperatively, more mild patients exhibited multigland disease (34.3 vs. 14.1 %, p < 0.01). When examining intraoperative PTH (IoPTH) kinetics where single adenomas were excised, the IoPTH fell at a rate of 6.9 pg/min in mild patients compared with 11.5 pg/min in the overt group (p < 0.01). Accordingly, 62.2 % of patients in the overt group and 53.3 % in the mild group were cured at 5 min postexcision (p < 0.01). There was no difference in the rates of persistence or recurrence between the groups, and disease-free survival estimates were identical (p = 0.27).

CONCLUSIONS

Patients with mild PHPT were more likely to have multigland disease and a slower decline in IoPTH, but these patients can be successfully treated with surgery.