Intraoperative adjuncts in surgery for primary hyperparathyroidism

Does Surgeon Volume Impact Morbidity Following Parathyroidectomy? A Study of 16,140 Parathyroidectomies from the UK Registry of Endocrine and Thyroid Surgery (UKRETS) Database

BACKGROUND

Outcomes in endocrine surgery have been shown to improve with surgeon volume. We aimed to study the effect of surgeon volume on morbidity following parathyroidectomy.

METHODS

UKRETS data from 2004 to 2019 was studied. Parathyroidectomies for primary hyperparathyroidism with complete data were included. Exclusion criteria were age <18 or >80 years; surgeons contributing <10 cases overall; and length of stay >28 days. Multivariable analysis was performed. Primary outcome was persistent hypercalcaemia; secondary outcomes were haemorrhage, length of stay, need for re-admission, post-operative hypocalcaemia, and need for calcium/vitamin D supplements to maintain eucalcaemia at 6 months.

RESULTS

153 surgeons undertook mean 22.5 (median 17, range 2-115) parathyroidectomies/year. Persistent hypercalcaemia affected 4.8% (776/16140) overall; 5.7% (71/1242) in surgeons undertaking < 10 cases/year; 5.1% (3339/6617) for 10-30 cases/year; 5.0% (270/5397) for 30-50 cases; and 3.3% (96/2884) for >50 cases/year. High-volume (>50 parathyroidectomies/year) surgeons operated 23.4% (809/3464) of negative localisation cases compared to 16.4% (2074/12676) of positive localisation cases. Persistent hypercalcaemia was almost twice as common in image negative (7.9%) compared to image-positive (4%) cases. Persistent hypercalcaemia was significantly more likely to occur in the low volume (<10 parathyroidectomies/year) group than high volume (>50 parathyroidectomies/year), regardless of image positivity (p = 0.0006). Surgeon volume significantly reduced persistent hypercalcaemia on multivariable analysis (OR = 0.878, 95%CI 0.842-0.914, p < 0.001), along with age, sex, and positive localisation. BNE and re-operation significantly increased persistent hypercalcaemia. Post-operative hypocalcaemia occurred in 3.2% (509/16040) and was reduced with increasing surgeon volume (OR = 0.951, 95%CI 0.910-0.993, p < 0.001). Haemorrhage and length of stay were not significantly associated with surgeon volume.

CONCLUSION

The incidence of persistent hypercalcaemia, post-operative hypocalcaemia, and persistent hypoparathyroidism decreased with increasing surgeon volume. The relative reduction in persistent hypercalcaemia with surgeon volume was similar in image negative and positive groups, but the absolute reduction was higher in image negative cases. Restricting image negative parathyroidectomy to high-volume surgeons could be considered.

The value of intraoperative parathyroid hormone monitoring in patients with primary hyperparathyroidism and varying baseline parathyroid hormone levels

BACKGROUND

When applying intraoperative parathyroid hormone monitoring (IOPTH) to patients with primary hyperparathyroidism (PHPT), there are established criteria predicting biochemical cure in patients with basal parathyroid hormone (PTH) levels in the medium range (100-400 pg/ml); however, there is a challenge concerning patients with low (less than 100 pg/ml) or high (more than 400 pg/ml) basal PTH levels. The aim of this study was to investigate the value of the 'Vienna criterion' applied during IOPTH in patients with PHPT and various basal PTH concentrations.

METHODS

Consecutive patients between 1999-2009 with a biochemical diagnosis of PHPT who underwent surgical parathyroidectomy were included. Based on preoperative PTH levels they were divided into three groups: group 1 (low) (<100 pg/ml), group 2 (medium) (100-400 pg/ml) and group 3 (high) (>400 pg/ml) basal PTH. PTH was measured at the start of the operation, when the gland was excised and then at 5, 10 and 15 min after. Calcium and PTH levels were measured at 7 days and 12 months postoperatively. Sensitivity, specificity, positive and negative predictive value, as well as accuracy of IOPTH were calculated for the different groups postoperatively.

RESULTS

675 patients with PHPT were analysed. Sensitivity and specificity were 83.7 per cent and 66.7 per cent in group 1 (n = 187), 90.7 per cent and 69.2 per cent in group 2 (n = 433), and 94.4 per cent and 100 per cent in group 3 (n = 55) to predict cure. Preoperative creatinine (p = 0.002) showed significant statistical difference between the groups but was not related to intraoperative PTH decline. At 12 months follow-up normocalcaemia was documented in 98.9 per cent in group 1, 99.0 per cent group 2, and 98.0 per cent of group 3 patients.

CONCLUSION

Normocalcaemia was predicted intraoperatively by applying the 'Vienna criterion' in 98 to 100 per cent and was confirmed after 12 months follow-up in up to 99.0 per cent of patients. Low specificity and a high false-negative rate in patients with low basal PTH show that other criteria might be better suited for this group.

Fluorescence Imaging Using Methylene Blue Sentinel Lymph Node Biopsy in Melanoma

Introduction

Fluorescence imaging of sentinel node biopsy in melanoma is a novel method. Both indocyanine green (ICG) and methylene blue (MB) have fluorescent properties. The aim of this study was to present, for the first time in a clinical series of patients, the possible usage of MB as a fluorescent dye for sentinel node biopsy during surgery for melanoma.

Material and methods

Twenty patients with skin melanoma, who were candidates for sentinel node biopsy were enrolled in our study. All patients underwent simultaneous use of standard nanocolloid and blue dye. Transcutaneous visualization of the sentinel node, visualization of lymphatic channels as well as sentinel node fluorescent visualization were all measured. We also performed calculations of Signal to Background ratios (SBR).

Results

In 15% (3/20) of patients, the fluorescent sentinel node was visible through the skin. The median SBR for the sentinel node visualization by fluorescence was 3.15 (range, 2.7–3.5). Lymphatic channels were visible in lymphatic tissue via fluorescence before visualization by the naked eye in 4 patients (20%). The median SBR ratio was 3.69 (range, 2.7–4.2). Sentinel nodes were visible by fluorescence in 13 cases (65%). The median SBR ratio was 2.49 (range, 1.5–5.7). No factors were found to be associated with fluorescent MB visualization of a sentinel node during biopsy.

Conclusion

This is the first clinical study presenting the usefulness of fluorescent sentinel node biopsy in melanoma patients using MB as a fluorophore. Further studies are necessary to provide methods for its’ clinical implementation.

Solar Heterogenous Photocatalytic Degradation of Methylthionine Chloride on a Flat Plate Reactor: Effect of pH and H2O2 Addition

Methylthionine chloride (MTC) is a compound with several applications both in the clinical and medical industries. Nevertheless, such compounds can become an environmental problem, as they are not properly treated by wastewater treatment plants. This objective of this work was to study MTC degradation in a flat plate reactor through solar photolysis and heterogeneous photocatalysis processes with TiO2 as a catalyst. In addition to the processes, three pH (3.5, 6.5, and 9) and the effect of H2O2 addition (no dose, 0.5, and 1 mM/L) were tested. The results show that acidic pH is the most appropriate for MTC degradation, which ranged between 56% and 68.7% for photolysis and between 76% and 86.7% in photocatalysis. The H2O2 addition resulted in lower degradation in all cases, leading the authors to conclude that the presence of peroxide actually hinders degradation in solar photolysis and photocatalysis processes. Statistical analysis showed that the constant rate reactions calculated for every process, under the same conditions of pH and H2O2 addition, are significantly different from one another, and the three factors considered for experimental design (process, pH, and H2O2) have a statistically significant effect on MTC degradation. The collector area per order confirmed higher efficiency for photocatalysis when compared to photolysis processes.

Primary hyperparathyroidism in adults-(Part II) surgical management and postoperative follow-up: Position statement of the Endocrine Society of Australia, The Australian & New Zealand Endocrine Surgeons, and The Australian & New Zealand Bone and Mineral Society

OBJECTIVE

To develop evidence-based recommendations to guide the surgical management and postoperative follow-up of adults with primary hyperparathyroidism.

METHODS

Representatives from relevant Australian and New Zealand Societies used a systematic approach for adaptation of guidelines (ADAPTE) to derive an evidence-informed position statement addressing eight key questions.

RESULTS

Diagnostic imaging does not determine suitability for surgery but can guide the planning of surgery in suitable candidates. First-line imaging includes ultrasound and either parathyroid 4DCT or scintigraphy, depending on local availability and expertise. Minimally invasive parathyroidectomy is appropriate in most patients with concordant imaging. Bilateral neck exploration should be considered in those with discordant/negative imaging findings, multi-gland disease and genetic/familial risk factors. Parathyroid surgery, especially re-operative surgery, has better outcomes in the hands of higher volume surgeons. Neuromonitoring is generally not required for initial surgery but should be considered for re-operative surgery. Following parathyroidectomy, calcium and parathyroid hormone levels should be re-checked in the first 24 h and repeated early if there are risk factors for hypocalcaemia. Eucalcaemia at 6 months is consistent with surgical cure; parathyroid hormone levels do not need to be re-checked in the absence of other clinical indications. Longer-term surveillance of skeletal health is recommended.

CONCLUSIONS

This position statement provides up-to-date guidance on evidence-based best practice surgical and postoperative management of adults with primary hyperparathyroidism.

Preoperative matching studies in the diagnosis of parathyroid adenoma for primary hyperparathyroidism: Can we avoid intraoperative PTH monitoring?

INTRODUCTION

We aim to determine the utility of intraoperative parathyroid hormone (IOPTH) monitoring in patients with matching preoperative ultrasound and mibi SPECT for primary hyperparathyroidism for a single adenoma.

METHODS

All patients who underwent minimally invasive parathyroidectomy (MIP) for pseudohypoparathyroidism (PHP) for a single parathyroid adenoma, were included. An Ultrasound and mibi SPECT were performed in all patients. We defined matching studies when both coincided in the localization of the adenoma. IOPTH was performed in all patients and analyzed in three occasions: a baseline measurement at the anesthetic induction, immediately before, and 15 min after gland excision. Success was defined during the third measurement as a drop of IOPTH of at least 50% compared to the previous maximum value after gland excision. Demographics, intraoperative, postoperative variables and the utility of IOPTH monitoring were analyzed.

RESULTS

A total of 218 MIP were performed. The average age was 60.1 years and 85% were female. Preoperative ultrasound and mibi SPECT coincided 100%. When the adenoma was localized, 15 min after its excision, IOPTH did not decrease in 9 patients (4.2%. OR 1.9%-7.69%); all of them underwent a bilateral neck exploration. The added-value of IOPTH accuracy for disease cure was 3.6%. There was a 99% of cure rate. The mean surgical time was 66.4 min and the waiting time for the third IOPTH result was 31 min. Performing IOPTH monitoring made the surgery about twice more expensive.

CONCLUSIONS

Preoperative matching ultrasound and mibi SPECT for parathyroid adenoma localization in PHP, could avoid IOPTH monitoring in minimally invasive parathyroidectomies.

Preoperative matching studies in the diagnosis of parathyroid adenoma for primary hyperparathyroidism: Can we avoid intraoperative PTH monitoring?

INTRODUCTION

We aim to determine the utility of intraoperative parathyroid hormone (IOPTH) monitoring in patients with matching preoperative ultrasound and mibi SPECT for primary hyperparathyroidism for a single adenoma.

METHODS

All patients who underwent minimally invasive parathyroidectomy (MIP) for pseudohypoparathyroidism (PHP) for a single parathyroid adenoma, were included. An Ultrasound and mibi SPECT were performed in all patients. We defined matching studies when both coincided in the localization of the adenoma. IOPTH was performed in all patients and analyzed in three occasions: a baseline measurement at the anesthetic induction, immediately before, and 15 minutes after gland excision. Success was defined during the third measurement as a drop of IOPTH of at least 50%compared to the previous maximum value after gland excision. Demographics, intraoperative, postoperative variables and the utility of IOPTH monitoring were analyzed.

RESULTS

A total of 218 MIP were performed. The average age was 60.1 years and 85% were female. Preoperative ultrasound and mibi SPECT coincided 100%. When the adenoma was localized, 15 minutes after its excision, IOPTH did not decrease in 9 patients (4.2% OR 1.9% - 7.69%); all of them underwent a bilateral neck exploration. The added-value of IOPTH accuracy for disease cure was 3.6%. There was a 99% of cure rate. The mean surgical time was 66.4 minutes and the waiting time for the third IOPTH result was 31minutes. Performing IOPTH monitoring made the surgery about twice more expensive.

CONCLUSIONS

Preoperative matching ultrasound and mibi SPECT for parathyroid adenoma localization in PHP, could avoid IOPTH monitoring in minimally invasive parathyroidectomies.

Methylene Blue-Current Knowledge, Fluorescent Properties, and Its Future Use

Methylene blue is a fluorescent dye discovered in 1876 and has since been used in different scientific fields. Only recently has methylene blue been used for intraoperative fluorescent imaging. Here, the authors review the emerging role of methylene blue, not only as a dye used in clinical practice, but also as a fluorophore in a surgical setting. We discuss the promising potential of methylene blue together with the challenges and limitations among specific surgical techniques. A literature review of PubMed and Medline was conducted based on the historical, current and future usage of methylene blue within the field of medicine. We reviewed not only the current usage of methylene blue, but we also tried to grasp its’ function as a fluorophore in five main domains. These domains include the near-infrared imaging visualization of ureters, parathyroid gland identification, pancreatic tumors imaging, detection of breast cancer tumor margins, as well as breast cancer sentinel node biopsy. Methylene blue is used in countless clinical procedures with a relatively low risk for patients. Usage of its fluorescent properties is still at an early stage and more pre-clinical, as well as clinical research, must be performed to fully understand its potentials and limitations.

Influence of common clinical variables on intraoperative parathyroid hormone monitoring during surgery for primary hyperparathyroidism

BACKGROUND

Intraoperative monitoring of parathyroid hormone (IOPTH) is a reliable method of predicting the cure of primary hyperparathyroidism (PHPT). The aim of this study is to assess whether common clinical variables (CCV) frequently encountered in patients with PHPT may affect the magnitude of PTH drop or the likelihood of patients meeting the intraoperative cure criterion.

DESIGN

Patients who were surgically cured from PHPT caused by single gland disease (SGD) and had full IOPTH protocol (4 measurements) were stratified according to age, gland weight, renal function, vitamin D status and severity of hypercalcemia. The percentage of IOPTH drop and the frequency of patients who had true positive IOPTH test results were compared among groups.

RESULTS

762 patients had surgery for PHPT, of whom 746 were (98%) cured. Of these 746 patients, 511 who had SGD and a full IOPTH protocol were included in this study. The median IOPTH drop was significantly higher among younger patients, those with severe hypercalcaemia at 5, 10, 15 min after gland excision, giant glands (at 5-min only), patients with vitamin D deficiency (at 10, 15 min), and those with normal renal function (at 15 min only). The likelihood of the patients meeting the intraoperative cure criterion was not significantly affected among the groups except in patients with mild hypercalcaemia, who were significantly less likely to have 50% IOPTH drop than those with severe hypercalcaemia at all time points. The frequency of mildly hypercalcaemic patients who met cure criterion was significantly improved by extending measurement to 15 min.

CONCLUSIONS

IOPTH monitoring has the ability to mitigate the variability of IOPTH kinetics associated with most clinical variables. Mildly hypercalcemic patients in particular may benefit from waiting for 15-min measurement before any surgical decision is made.

Use of a Sestamibi-only Approach to Routine Minimally Invasive Parathyroidectomy

We performed this study to compare a sestamibi-only radio-guided approach (MIBI) versus using intraoperative parathyroid hormone monitoring (IOPTH) in the performance of minimally invasive parathyroidectomy (MIP) in patients with a clearly positive preoperative sestamibi scan from January 2000 to June 2010. Five of 81 patients in the MIBI group required additional surgery, three at the time of MIP when the intraoperative findings were in conflict with the preoperative sestamibi scan and two required a second operation as a result of an undiscovered second adenoma. In the IOPTH group, five patients had an unnecessary bilateral neck exploration as a result of an inadequate drop in PTH levels, whereas six had their disease cured because the PTH levels predicted additional pathology. One patient in the IOPTH group remains hypercalcemic and represents the only surgical failure in this study. The MIBI group had a shortened operating room time and less cost ( P < 0.001). No deaths or complications, including recurrent laryngeal nerve injuries, occurred in this study. Although both strategies are effective in managing hyperparathyroidism, a MIBI-only approach is less expensive and has shorter operative times with an occasional need for reoperation, whereas the IOPTH group results in more extensive surgery that will occasionally be unnecessary.

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.

First ever case report of co-occurrence of hobnail variant of papillary thyroid carcinoma and intrathyroid parathyroid adenoma in the same thyroid lobe

•

First reported case of hobnail variant of papillary thyroid cancer and Intrathyroid parathyroid adenoma occurring within same thyroid lobe.

•

Next-generation sequencing of the mutation spectrum of hobnail variant of papillary thyroid cancer showed BRAFV600E mutation.

•

Studies that define other molecular abnormalities may be useful as therapeutic targets.

Introduction

The hobnail variant of papillary thyroid cancer (PTC) is rare. Intrathyroid parathyroid adenoma (ITPA) is also rare. Co-ocurrence of PTC and ITPA in the same thyroid lobe is extremely rare. Likewise, primary hyperparathyroidism with such non-medullary thyroid carcinoma is rare. The specific molecular profile of hobnail PTC (HPTC) is different from the classic, poorly differentiated and anaplastic variants and may contribute to its aggressive behavior. HPTC’s genetic profile remains unclear.

Presentation of case

A 61-year-old woman presented to our endocrine clinic with generalized aches, bone pain, polyuria, and right neck swelling of a few months’ duration. Laboratory findings revealed hypercalcemia and hyperparathyroidism. Ultrasound of the neck showed 4.6 cm complex nodule within the right thyroid lobe. Sestamibi scan suggested parathyroid adenoma in the right thyroid lobe. Fine-needle aspiration (FNA) revealed atypical follicular lesion of undetermined significance. She underwent right lobectomy, which normalized the intraoperative intact parathyroid hormone levels. Final pathology with immunohistochemical stains demonstrated HPTC and IPTA (2 cm each). Next-generation sequencing investigated the mutation spectrum of HPTC and detected BRAFV600E mutation.

Conclusions

A parathyroid adenoma should not exclude the diagnosis of thyroid carcinoma. Thyroid evaluation is needed for patients with primary hyperparathyroidism to prevent missing concurrent thyroid cancers. Cytomorphologic features to distinguish thyroid from parathyroid cells on FNA cytology must be considered. Immunohistochemical stains are important. BRAFV600E is the most common mutation in HPTC. This is possibly the first reported case of HPTC and ITPA co-occurring within the same thyroid lobe. Studies that define other molecular abnormalities may be useful as therapeutic targets.

The role of intraoperative parathyroid hormone (IOPTH) determination for identification and surgical strategy of sporadic multiglandular disease in primary hyperparathyroidism (pHPT)

Intraoperative PTH monitoring (IOPTH) made minimally invasive parathyroidectomy in patients with primary HPT possible. However, with the increasing accuracy of preoperative localization studies there is a growing discussion if IOPTH is necessary in patients with localized single gland disease (concordant preoperative localization studies). Different interpretation criteria have been developed - each with their particular advantages and disadvantages, but the "perfect" criterion is still missing. Despite several pitfalls, which can be recognized intraoperatively and do not necessarily lead to a more extensive surgery, IOPTH seems to be a useful adjunct in surgery for PHPT. However, according to current guidelines, selected patients may be operated without IOPTH but need to be informed about the possibly increased risk of recurrent disease.

Parathyroid identification by autofluorescence - preliminary report on five cases of surgery for primary hyperparathyroidism

Background

Intra-operative identification of parathyroid glands is often a challenge for surgeons performing parathyroid or thyroid surgery. Parathyroid glands stimulated by near-infrared light emit autofluorescence, which allows their discrimination from all other tissues in the region, and this may be of value during thyroid and parathyroid surgery. In this study, we present the results of the utilization of a low-cost device developed for the identification of parathyroid glands in surgery for primary hyperparathyroidism.

Case presentation

In 5 patients operated in our hospital with the diagnosis of primary hyperparathyroidism and non-concordant ultrasonography and Sestamibi scan, we used a 780 nm Light Emitting Diode (LED) to stimulate the cervical area. The resulting autofluorescence was visualized with night vision goggles with a 832 nm filter assembled.

In all the five patients, an easily distinguishable nodule was identified and excised, and confirmed as parathyroid adenoma by histological exam. Intra-operative PTH assay showed significant decrease compared with basal values, fulfilling the Miami Criteria for surgical success in use in our institution.

Conclusion

The utilization of autofluorescence for intra-operative identification of parathyroid glands may have a clinical application in surgery for primary hyperparathyroidism, being of special utility when ultrasonography and Sestamibi Scan are non concordant.

Practice Patterns in Parathyroid Surgery: A Survey of Asia-Pacific Parathyroid Surgeons

BACKGROUND

Practice variations exist amongst parathyroid surgeons depending on their expertise and resources. Our study aims to elucidate the choice of surgical techniques and adjuncts used in parathyroid surgery by surgeons in the Asia-Pacific region.

METHODS

A 25-question online survey was sent to members of five endocrine surgery associations. Questions covered training background, practice environment and preferred techniques in parathyroid surgery. Respondents were divided into three regions: Australia/New Zealand, South/South East Asia and East Asia, and responses were analysed according to region, specialty, case volume and years in practice.

RESULTS

One hundred ninety-six surgeons returned the questionnaire. Most surgeons (98%) routinely perform preoperative imaging, with 75% preferring dual imaging with ^99mTcsestamibi and ultrasound. Ten per cent of surgeons use parathyroid 4DCT as first-line imaging, more commonly in East Asia (p = 0.038). Minimally invasive parathyroidectomy is the favoured technique of choice (97%). Most surgeons reporting robotic or endoscopic approaches are from East Asia. Rapid intraoperative parathyroid hormone is accessible to just under half of the surgeons but less available in Australian/New Zealand (p < 0.001). The use of intraoperative neuromonitoring is not commonly used, even less so amongst Asian surgeons (p = 0.048) and surgeons with low case load (p = 0.013).

CONCLUSION

Dual localisation techniques are the preferred choice of investigations in preparation for parathyroid surgery, with minimally invasive surgery without neuromonitoring the preferred approach. Use of adjuncts is sporadic and limited to certain centres.

Is Unilateral Neck Surgery Feasible in Patients with Sporadic Primary Hyperparathyroidism and Double Negative Localisation?

INTRODUCTION

Ultrasound and Tc99mMIBI scans are used to localise parathyroid tumours in sporadic primary hyperparathyroidism (pHPT). Intra-operative PTH (ioPTH) assay facilitates unilateral neck exploration (UNE). When both ultrasound and MIBI are negative, it is our policy to explore the left side of the neck and only proceed to bilateral neck exploration (BNE) when either a tumour is not found or when ioPTH does not fall to >50% of the highest pre-excision value. The aim of this study was to investigate the outcome of our approach to 'double negative' patients.

METHODS

A retrospective analysis of patients undergoing primary parathyroidectomy for pHPT. Data were obtained from a prospective surgical database and the hospital electronic patient record.

RESULTS

Between January 2004 and November 2014, 746 patients underwent a parathyroidectomy for pHPT. Those who did not have both pre-operative scans, ioPTH or a minimum of 6-month follow-up were excluded. Of 552 patients, 111 (20%) had double negative scans (group A), and in 441, either one or both scans were positive (group B). Median age was 61.5 years (range 10-88). Pre-operative PTH level was significantly lower in group A: 11.8 pmol/l (range 3.1-38.8) versus 14.9 pmol/l (range 2.8-101.6; P < 0.01). Median tumour weight was significantly lower in group A: 280 mg (range 50-3710) versus 573 mg (range 10-12,000; P < 0.01). Overall rate of multiple gland disease (MGD) was 11%; 24% in group A and 7% in group B (P < 0.01). Overall rate of UNE in Group A was 28% and converse to the rate in Group B (76%; P < 0.01). Sensitivity and specificity of ioPTH to detect MGD were 98 and 98% in Group A versus 98 and 100% in Group B. First-time cure rate was 92.7% in group A and 96.8% in group B (P < 0.05).

CONCLUSION

A double negative scan is associated with small tumours and higher rates of MGD. Despite these challenges, surgery is successful in this group of patients reinforcing the message that negative localisation is not a contraindication for parathyroidectomy. We demonstrated that it is feasible to offer unilateral neck surgery to 28% of patients with double negative scans. A randomised trial is needed to compare BNE with ioPTH/UNE in this select population.

Sporadic multiple parathyroid gland disease--a consensus report of the European Society of Endocrine Surgeons (ESES)

BACKGROUND

Sporadic multiglandular disease (MGD) has been reported in literature in 8-33 % of patients with primary hyperparathyroidism (pHPT). This paper aimed to review controversies in the pathogenesis and management of sporadic MGD.

METHODS

A literature search and review was made to evaluate the level of evidence concerning diagnosis and management of sporadic MGD according to criteria proposed by Sackett, with recommendation grading by Heinrich et al. and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled 'Hyperparathyroidism due to multiple gland disease: An evidence-based perspective'.

RESULTS

Literature reports no prospective randomised studies; thus, a relatively low level of evidence was achieved. Appropriate surgical therapy of sporadic MGD should consist of a bilateral approach in most patients. Unilateral neck exploration guided by preoperative imaging should be reserved for selected patients, performed by an experienced endocrine surgeon and monitored by intraoperative parathormone assay (levels of evidence III-V, grade C recommendation). There is conflicting or equally weighted levels IV-V evidence supporting that cure rates can be similar or worse for sporadic MGD than for single adenomas (no recommendation). Best outcomes can be expected if surgery is performed by an experienced parathyroid surgeon working in a high-volume centre (grade C recommendation). Levels IV-V evidence supports that recurrent/persistence pHPT occurs more frequently in patients with double adenomas hence in situations where a double adenoma has been identified, the surgeon should have a high index of suspicion during surgery and postoperatively for the possibility of a four-gland disease (grade C recommendation).

CONCLUSIONS

Identifying preoperatively patients at risk for MGD remains challenging, intraoperative decisions are important for achieving acceptable cure rates and long-term follow-up is mandatory in such patients.

[Not Available]

BACKGROUND

Methylene blue is used in medical practice for various reasons. Recent findings point to a potential interaction with serotonin reuptake inhibitors (SRIs) that could lead to serotonergic toxicity.

OBJECTIVE

To describe the risk of serotonergic toxicity associated with the interaction between methylene blue and SRIs.

DATA SOURCES

Relevant publications were searched systematically via MEDLINE (1946 to March 21, 2013) and Embase (1974 to 2013, week 11) with the following search terms: "methylene blue", "methylthioninium", "monoamine oxidase inhibitors", "serotonin reup-take inhibitors", and "serotonin syndrome". No restrictions were applied in relation to the indication for methylene blue or the language of publication. The reference lists of identified articles were also searched.

STUDY SELECTION AND DATA EXTRACTION

Eighteen case reports and 2 case series were identified for inclusion. To date, no randomized controlled trials have been published.

DATA SYNTHESIS

The first case report indicating suspicion of an interaction between methylene blue and SRIs was published in 2003. Seventeen other case reports describing the same type of interaction have been published since then. The 2 case series provided data from about 325 parathyroidectomies in which methylene blue was used for staining. The 17 patients who experienced central nervous system toxicity were all taking SRIs in the preoperative period.

CONCLUSION

When administered in combination with SRIs, methylene blue may lead to serotonergic toxicity at doses as low as 0.7 mg/kg. Methylene blue would seem to have monoamine oxidase A inhibitory properties. Precautions should be taken to avoid this interaction. [Publisher's translation].

Intraoperative guidance in parathyroid surgery using near-infrared fluorescence imaging and low-dose Methylene Blue

BACKGROUND

Identification of diseased and normal parathyroid glands during parathyroid surgery can be challenging. The aim of this study was to assess whether near-infrared (NIR) fluorescence imaging using administration of a low-dose Methylene Blue (MB) at the start of the operation could provide optical guidance during parathyroid surgery and assist in the detection of parathyroid adenomas.

METHODS

Patients diagnosed with primary hyperparathyroidism planned for parathyroidectomy were included. Patients received 0.5 mg/kg MB intravenously directly after start of anesthesia. During the operation, NIR fluorescence imaging was performed to identify parathyroid adenomas. Imaging results were compared with a previous published feasibility study in which 12 patients received MB after intraoperative identification of the adenoma.

RESULTS

A total of 13 patients were included in the current study. In 10 of 12 patients with a histologically proven adenoma, the adenoma was fluorescent. Mean signal to background ratio was 3.1 ± 2.8. Mean diameter of the resected lesions was 17 ± 9 mm (range 5-28 mm). Adenomas could be identified up to 145 minutes after administration, which was the longest timespan until resection. Interestingly, in 3 patients, a total of 6 normal parathyroid glands (median diameter 2.5 mm) with a signal to background ratio of 1.8 ± 0.4 were identified using NIR fluorescence imaging.

CONCLUSION

Early administration of low-dose MB provided guidance during parathyroidectomy by identifying both parathyroid adenomas and normal parathyroid glands. In patients in whom difficult identification of the parathyroid adenoma is expected or when normal glands have to be identified, the administration of MB may improve surgical outcome.

Aetiology, Diagnosis and Surgical Treatment of Primary Hyperparathyroidism in Children: New Trends

Primary hyperparathyroidism (PHPT) in children is a rare disorder with sharp contrasts in its presentation and aetiology compared with the disease process in adults. This review outlines the current literature, which is limited to about 200 cases, with reference to the aetiology, clinical features, outcomes of investigations, and surgery in children affected by PHPT. Familial conditions account for almost half of all cases of PHPT in children, suggesting that routine genetic testing would be appropriate. Neonatal severe hyperparathyroidism requires urgent medical attention, and performing total parathyroidectomies offers cure, though conservative management is successful in selected cases. Familial hyperparathyroidism in older children can be caused by conditions such as multiple endocrine neoplasia types 1 and 2a, hyperparathyroidism-jaw tumour syndrome and familial hyperparathyroidism. The role of surgery for this group is discussed. The use of ultrasound and MIBI (99mTc-methoxyisobutylnitrile) scanning appears to accurately localise solitary adenomas in sporadic PHPT, thereby supporting the role of minimally invasive parathyroidectomy in children. © 2015 S. Karger AG, Basel.

The current status of intraoperative iPTH assay in surgery for primary hyperparathyroidism

Intraoperative intact parathyroid hormone (iPTH) monitoring has been accepted by many centers specializing in parathyroid surgery as a useful adjunct during surgery for primary hyperparathyroidism. This method can be utilized in three discreet modes of application: (I) to guide surgical decisions during parathyroidectomy in one of the following clinical contexts: (i) to confirm complete removal of all hyperfunctioning parathyroid tissue, which allows for termination of surgery with confidence that the hyperparathyroid state has been successfully corrected; (ii) to identify patients with additional hyperfunctioning parathyroid tissue following the incomplete removal of diseased parathyroid/s, which necessitates extended neck exploration in order to minimize the risk of operative failure; (II) to differentiate parathyroid from non-parathyroid tissue by iPTH measurement in the fine-needle aspiration washout; (III) to lateralize the side of the neck harboring hyperfunctioning parathyroid tissue by determination of jugular venous gradient in patients with negative or discordant preoperative imaging studies, in order to increase the number of patients eligible for unilateral neck exploration. There are many advantages of minimally invasive parathyroidectomy guided by intraoperative iPTH monitoring, including focused dissection in order to remove the image-indexed parathyroid adenoma with a similar or even higher operative success rate, lower prevalence of complications and shorter operative time when compared to conventional bilateral neck exploration. However, to achieve such excellent results, the surgeon needs to be aware of hormone dynamics during parathyroidectomy and carefully choose the protocol and interpretation criteria that best fit the individual practice. Understanding the nuances of intraoperative iPTH monitoring allows the surgeon for achieving intraoperative confidence in predicting operative success and preventing failure in cases of unsuspected multiglandular disease, while safely limiting neck exploration in the majority of patients with sporadic primary hyperparathyroidism. Thus, parathyroidectomy guided by intraoperative iPTH monitoring for the management of sporadic primary hyperparathyroidism is an ideal option for the treatment of this disease entity. However, the cost-benefit aspects of the standard application of this method still remain a matter of controversy.

Intraoperative near-infrared fluorescence imaging of parathyroid adenomas with use of low-dose methylene blue

BACKGROUND

Intraoperative identification of parathyroid adenomas can be challenging. We hypothesized that low-doses methylene blue (MB) and near-infrared fluorescence (NIRF) imaging could be used to identify parathyroid adenomas intraoperatively.

METHODS

MB was injected intravenously after exploration at a dose of 0.5 mg/kg into 12 patients who underwent parathyroid surgery. NIRF imaging was performed using the Mini-FLARE imaging system.

RESULTS

In 10 of 12 patients, histology confirmed a parathyroid adenoma. In 9 of these patients, NIRF could clearly identify the parathyroid adenoma during surgery. Seven of these 9 patients had a positive preoperative (99m) Tc-sestamibi single photon emission CT (SPECT) scan. Importantly, in 2 patients, parathyroid adenomas could be identified only using NIRF.

CONCLUSION

This is the first study to show that low-dose MB can be used as NIRF tracer for identification of parathyroid adenomas, and suggests a correlation with preoperative (99m) Tc-sestamibi SPECT scanning.

Open mini-incision parathyroidectomy for solitary parathyroid adenoma

Parathyroid surgery is the acceptable definitive treatment for primary hyperparathyroidism (pHPT) due to parathyroid adenoma. Open mini-incision parathyroidectomy (O-MIP) has an excellent cure rate and minimal morbidity. We aim to demonstrate the safety, efficacy and subjective patient satisfaction of O-MIP and investigate the accuracy of pre-operative radiological localisation in relation to operative findings. A retrospective review of patients who underwent O-MIP for pHPT due to solitary parathyroid adenoma from April 2006 to August 2012 was performed. All patients were initially investigated by an endocrinologist to confirm pHPT with pre-operative localisation imaging using ultrasound scan (USS) and 99mTc-sestamibi (MIBI). One hundred and fifty consecutive patients were included with a median age of 62 years. Pre-operative USS and MIBI scans were concordant in 71 % of cases. In combined modality (USS and MIBI), localisation was 94.8 % accurate. There was 95.5 % identification of parathyroid tissue confirmed by intra-operative frozen section. Ninety-one percent of patients were treated as a day case. The median operative time was 60 min. The mean pre-operative calcium level was 2.98 mmol/l, and the short-to-medium term mean calcium level was 2.49 (Paired t test, p < 0.001). There was no significant complication. O-MIP confers significant advantages over the traditional gold standard treatment of bilateral neck exploration. Accurate localisation is the key to successful O-MIP. In experienced hands, ultrasound and MIBI may be the only pre-operative investigations required for accurate localisation.

Could the eZ-SCOPE AN gamma camera replace intraoperative measurement of iPTH for PHPT?

Intraoperative intact parathyroid hormone (iPTH) measurements have been proposed as an effective assay in surgery for primary hyperparathyroidism (PHPT). We have demonstrated the efficiency of the use of a hand-held gamma camera, eZ-SCOPE AN, with technetium-99m sestamibi (Tc-MIBI) scintigraphy for navigation surgery for PHPT. The aim of this preliminary study was to assess the possibility that the eZ-SCOPE AN can replace the measurement of intraoperative iPTH in surgery for PHPT. Sixteen consecutive patients with documented primary hyperparathyroidism underwent surgery using this compact camera. iPTH was routinely measured preoperatively and 10 minutes after the complete removal of adenoma. All patients had a well-defined parathyroid lesion identified on preoperative Tc-MIBI. The eZ-SCOPE revealed hyperfunctioning parathyroid glands in all cases. iPTH levels were decreased in all cases after the removal of adenomas. Our results suggest that this gamma camera is useful for confirming complete resection of endocrinologically active tissue in surgery for PHPT. In selective patients with scan-positive cases identified by preoperative Tc-MIBI, the eZ-SCOPE may replace the intraoperative iPTH assay in surgery for PHPT.

Systematic review of intravenous methylene blue in parathyroid surgery

Background

Methylene blue is an intraoperative adjunct for localization of enlarged parathyroid glands. The availability of preoperative and other intraoperative localization methods, and the reported adverse effects of methylene blue make its routine use debatable. The aim of this study was to perform a systematic review of the use of methylene blue in parathyroidectomy.

Methods

A systematic review of English-language literature in MEDLINE and Scopus databases on the use of intravenous methylene blue in parathyroid surgery was carried out.

Results

There were no randomized clinical trials. Thirty-nine observational studies were identified, of which 33 did not have a control arm. The overall median staining rate for abnormal parathyroid glands was 100 per cent. The median cure rates in the methylene blue and no-methylene blue arms were 100 and 98 per cent respectively. Neurotoxicity was reported in 25 patients, all of whom were taking serotonergic medication.

Conclusion

Observational evidence suggests that methylene blue is efficacious in identifying enlarged parathyroid glands. Toxicity appears to be mild in the absence of concomitant use of serotonin reuptake inhibitors. The effectiveness of methylene blue in the context of currently used preoperative and intraoperative localization techniques has yet to be shown.

Tumor proximity to the recurrent laryngeal nerve in patients with primary hyperparathyroidism undergoing parathyroidectomy

BACKGROUND

Recurrent laryngeal nerve (RLN) injury is a rare complication for patients undergoing neck exploration for primary hyperparathyroidism (pHPT). Distances between RLNs and parathyroid adenomas have not been previously published. In this study we used a RLN monitor to identify the RLN and to measure the proximity to parathyroid tumors.

METHODS

Patients with pHPT (n = 136) underwent neck exploration and had the clinical data recorded prospectively. Adenomas were recorded in 1 of 4 locations (right upper, right lower, left upper, left lower). Measurement of RLN to adenoma distances were recorded intraoperatively with the gland in situ. The RLN location was confirmed with a RLN monitor.

RESULTS

The average RLN to adenoma distance was 0.52 ± 0.52 cm. Adenomas in the right upper position were significantly closer to the nerve (0.25 ± 0.39 cm) compared with adenomas in the left upper (0.48 ± 0.61 cm, p = .03), left lower (0.70 ± 0.53 cm, p < .001), and right lower position (1.02 ± 0.56 cm, p < .001). Left upper adenomas were also significantly closer to the nerve compared with right lower adenomas (p < .001). Adenomas in the right upper position abutted the nerve more often (47 %) compared with adenomas in other positions (p = .001). There were no perioperative characteristics that predicted tumor abutment. There were no permanent RLN injuries.

CONCLUSION

In patients with sporadic pHPT, parathyroid adenomas in the right upper location have, on average, greater proximity to the RLN and are more often directly abutting compared with adenomas in other locations.

Use of a Handheld, Semiconductor (Cadmium Zinc Telluride)-Based Gamma Camera in Navigation Surgery for Primary Hyperparathyroidism

The recent development of gamma-ray probes makes it possible to perform radioguided surgery for primary hyperparathyroidism (PHPT). There have only been a few reports, however, regarding the use of a handheld gamma camera to detect parathyroid adenoma intraoperatively. The aim of this preliminary study was to assess the efficiency of a semiconductor gamma camera (eZ-SCOPE AN) in navigation surgery for PHPT. The eZ-SCOPE is designed to be used as a handheld, regional diagnostic imaging device. Eleven consecutive patients with documented primary hyperparathyroidism underwent surgery using this compact camera. Scintigraphy images of the neck by eZ-SCOPE were acquired: 1) before skin incision; 2) after adenoma location; 3) after adenoma excision; and 4) ex vivo imaging of the specimen. In scan-positive cases by preoperative Tc-MIBI, the eZ-SCOPE revealed parathyroid adenoma in all cases (100%), whereas ultrasound and CT showed a single adenoma in 63.6 and 72.7 per cent of cases, respectively. Navigation surgery for PHPT using the eZ-SCOPE permitted intraoperative identification and removal of parathyroid adenoma in all cases. Scintigraphy images of the neck by eZ-SCOPE also revealed a single adenoma even before skin incision. Our results suggest that Tc-MIBI scintigraphy with the eZ-SCOPE is useful for navigation surgery for PHPT. The eZ-SCOPE is useful for skin marking and could be easily applied for minimally invasive radioguided parathyroidectomy in scan-positive cases.

Intraoperative adjuncts for parathyroid surgery

In recent years, parathyroid surgery has evolved from traditional bilateral neck exploration to minimal invasive parathyroidectomy. This trend became possible due to preoperative localization imaging that guides the surgeon in the search for a parathyroid adenoma. Intraoperative adjuncts are complementary to preoperative localization and assist in localizing parathyroid glands, confirming parathyroid tissue and establishing a cure. Institutions and surgeons utilize different intraoperative adjuncts in different protocols with varying results. The purpose of this article is to review the available intraoperative adjuncts to parathyroid surgery and critically evaluate their utility, accuracy and their added value to the surgeon.

[Intraoperative parathyroid hormone determination for primary hyperparathyroidism]

Intraoperative parathyroid hormone measurement (IOPTH) has proved to be an important promoter for focused and minimally invasive parathyroidectomy procedures in primary hyperparathyroidism. IOPTH enables multiglandular disease to be excluded with a high degree of certainty at the time of operation. The choice of the cut-off value for IOPTH as the criterion for success is of utmost importance with respect to the prognosis for operative success (biochemical healing). Advantages and disadvantages of the variety of existing IOPTH success criteria are confusing and their assessment is contradictory. Particularly with respect to cost-benefit aspects the standard application of IOPTH as "biochemical frozen section" even in conventional open parathyroidectomy remains a matter of controversy. This article gives an up-date on current knowledge and provides practical guidelines for clinical use of IOPTH.