Intraoperative Parathyroid Hormone Monitoring Research Articles

Trends in using intraoperative parathyroid hormone monitoring during parathyroidectomy: Protocol and rationale for a cross-sectional survey study of North American surgeons.

Hyperparathyroidism is a common endocrine disorder that occurs secondary to abnormal parathyroid gland functioning. Depending on the type of hyperparathyroidism, surgical extirpation of hyperfunctioning parathyroid glands can be considered for disease cure. Intraoperative parathyroid hormone (IOPTH) monitoring improves outcomes in patients undergoing surgery for primary hyperparathyroidism, but studies are needed to characterize its institutional adoption and its role in surgery for secondary and tertiary hyperparathyroidism, as these entities can be difficult to cure. Hence, we will perform a cross-sectional survey study of surgeon rationale, operational details, and barriers associated with IOPTH monitoring adoption across North America. We will utilize a convenience sampling technique to distribute an online survey to head and neck surgeons and endocrine surgeons across North America. This survey will be distributed via email to three North American professional societies (i.e., Canadian Society for Otolaryngologists-Head and Neck Surgeons, American Head and Neck Society, and American Association of Endocrine Surgeons). The survey will consist of 30 multiple choice questions that are divided into three concepts: (1) participant demographics and training details, (2) details of surgical adjuncts during parathyroidectomy, and (3) barriers to adoption of IOPTH. Descriptive analyses and multiple logistic regression will be used to evaluate the impact of demographic, institutional, and training variables on the use of IOPTH monitoring in surgery for all types of hyperparathyroidism and barriers to IOPTH monitoring adoption. Ethics approval was obtained by the Hamilton Integrated Research Ethics Board (2024-17173-GRA). These findings will characterize surgeon and institutional practices with regards to IOPTH monitoring during parathyroid surgery and will inform future trials aimed to optimize the use of IOPTH monitoring in secondary and tertiary hyperparathyroidism.

1053 Parathyroid Phenomenon Causing Primary Hyperparathyroidism: A Case for Surgeons, Radiologists and Pathologists

Abstract Background Parathyroid lipoadenomas are a rare parathyroid phenomenon and an unusual cause of primary hyperparathyroidism. The histological composition of these neoplasms makes them a diagnostic challenge, as their high adipose content leads to difficulty localising them on imaging and can lead pathologists towards a wrong diagnosis. There are less than 100 cases in the literature since they were first described in 1958, and to our knowledge this is the largest parathyroid lipoadenoma to be reported. Method A minimally invasive parathyroidectomy with intraoperative parathyroid hormone monitoring was performed in the case of a male with a large neck mass and symptomatic primary hyperparathyroidism. Results A giant parathyroid lipoadenoma was excised, with an appropriate decrease in intraoperative parathyroid hormone level observed. The patient has been cured of his primary hyperparathyroidism, with no issues following his discharge from our institution. Conclusions We highlight the importance of having the parathyroid lipoadenoma as a differential diagnosis for patients who develop primary hyperparathyroidism.

Reflections on intraoperative PTH monitoring and frozen biopsy in managing persistent hypercalcemia post-kidney transplant.

Reflections on intraoperative PTH monitoring and frozen biopsy in managing persistent hypercalcemia post-kidney transplant.

Ultrafast intraoperative parathyroid hormone monitoring system: prospective, multicentre, clinical validity study.

Intraoperative parathyroid hormone (PTH) monitoring is a proven and reliable adjunct to parathyroid surgery, able to improve the outcomes and efficiency of the diagnostic and therapeutic pathway for patients with primary hyperparathyroidism. This study evaluated the innovative, compact, fully automated NBCL CONNECT Analyzer, which can measure whole-blood PTH in 5 min. A prospective multicentre study was conducted in stages: results reviews, recommendations, and implementation of improvements to the mechanical design, components of cartridges, calibration, and sampling protocols. Patients undergoing parathyroidectomy had PTH levels measured on the Analyzer and main laboratory platforms, either Roche or Abbott. The Miami criterion of a 50% drop in PTH concentration was used to define biochemical cure during surgery, and normal postoperative calcium level as cure of primary hyperparathyroidism. Measurements on the Analyzer were done by laboratory staff in London and nurses in Stuttgart. The Pearson coefficient (R) and Wilcoxon test were used for statistical analysis. Some 234 patients (55 male, 179 female) with a median age of 58.5 (age full range 15-88) years underwent parathyroidectomy (195 minimally invasive, 38 bilateral neck exploration, 1 thoracoscopic; 12 conversions) for primary hyperparathyroidism between November 2021 and July 2022. Primary hyperparathyroidism was cured in 225 patients (96.2%). The sensitivity, specificity, and overall accuracy of the Analyzer assay in predicting biochemical cure were 83.9, 100, and 84.8% in phase 1; 91.2, 100, and 91.3% in phase 2; and 98.6, 100, and 98.6% in phase 3. There were no false-positive results (positive predictive value 100%). Correlations between Analyzer measurements and those obtained using the Roche device were very strong (R = 0.98, P < 0.001 in phase 1; R = 0.92, P < 0.001 in phase 2; R = 0.94, P < 0.001 in phase 3), and correlations for Analyzer readings versus those from the Abbott platform were strong (R = 0.82, P < 0.001; R = 0.89, P < 0.001; R = 0.91, P < 0.001). The Analyzer showed continued good mechanical performance, with stable and repeatable operations (calibrations, quality controls). Introducing a stricter sampling protocol and improvements in the clot-detecting system led to a decrease in the number of clotted samples and false-negative results. Outcomes were not affected by measurements performed either by nurses or laboratory staff. Intraoperative PTH monitoring during parathyroid surgery can be done accurately, simply, and quickly in whole blood using the Analyzer.

Characteristics, management and outcomes of primary hyperparathyroidism from 2009 to 2021: a single centre report from South Africa

BackgroundThere has been a notable shift towards the diagnosis of less severe and asymptomatic primary hyperparathyroidism (PHPT) in developed countries. However, there is a paucity of recent data from sub-Saharan Africa (SSA), and also, no reported data from SSA on the utility of intra-operative parathyroid hormone (IO-PTH) monitoring. In an earlier study from Inkosi Albert Luthuli Central Hospital (IALCH), Durban, South Africa (2003–2009), majority of patients (92.9%) had symptomatic disease. The aim of this study was to evaluate the clinical profile and management outcomes of patients presenting with PHPT at IALCH.MethodsA retrospective chart review of patients with PHPT attending the Endocrinology clinic at IALCH between July 2009 and December 2021. Clinical presentation, laboratory results, radiologic findings, surgical notes and histology were recorded.ResultsAnalysis included 110 patients (87% female) with PHPT. Median age at presentation was 57 (44; 67.5) years. Symptomatic disease was present in 62.7% (n:69); 20.9% (n:23) had a history of nephrolithiasis and 7.3% (n:8) presented with previous fragility fractures. Mean serum calcium was 2.87 ± 0.34 mmol/l; median serum-PTH was 23.3 (15.59; 45.38) pmol/l, alkaline phosphatase 117.5 (89; 145.5) U/l and 25-hydroxyvitamin-D 42.9 (33.26; 62.92) nmol/l. Sestamibi scan (n:106 patients) identified an adenoma in 83.02%. Parathyroidectomy was performed on 84 patients with a cure rate of 95.2%. Reasons for conservative management (n:26) included: no current surgical indication (n:7), refusal (n:5) or deferral of surgery (n:5), loss to follow-up (n:5) and assessed as high anaesthetic risk (n:4). IO-PTH measurements performed on 28 patients indicated surgical success in 100%, based on Miami criteria. Histology confirmed adenoma in 88.1%, hyperplasia in 7.1% and carcinoma in 4.8%. Post-operative hypocalcaemia developed in 30 patients (35.7%), of whom, 14 developed hungry bone syndrome (HBS). In multivariate analysis, significant risk factors associated with HBS included male sex (OR 7.01; 95% CI 1.28, 38.39; p 0.025) and elevated pre-operative PTH (OR 1.01; 95% CI 1.00, 1.02; p 0.008).ConclusionsThe proportion of asymptomatic PHPT has increased at this centre over the past decade but symptomatic disease remains the dominant presentation. Parathyroidectomy is curative in the majority of patients. IO-PTH monitoring is valuable in ensuring successful surgery.

Microwave ablation of ectopic parathyroid adenoma in the carotid sheath with intraoperative parathyroid hormone monitoring: a case description.

Microwave ablation of ectopic parathyroid adenoma in the carotid sheath with intraoperative parathyroid hormone monitoring: a case description.

Predictive factors for persistent hypercalcemia following parathyroidectomy in patients with persistent hyperparathyroidism after kidney transplantation: a retrospective cohort study.

Surgery for irreversible hyperparathyroidism is the preferred management for kidney transplant patients. The authors analyzed the factors associated with persistent hypercalcemia after parathyroidectomy in kidney transplant patients and evaluated the appropriate extent of surgery. The authors retrospectively analyzed 100 patients who underwent parathyroidectomy because of persistent hyperparathyroidism after kidney transplantation at a tertiary medical center between June 2011 and February 2022. Patients were divided into two groups: 22 with persistent hypercalcemia after parathyroidectomy and 78 who achieved normocalcemia after parathyroidectomy. Persistent hypercalcemia was defined as having sustained hypercalcemia (≥10.3mg/dl) 6 months after kidney transplantation. The authors compared the biochemical and clinicopathological features between the two groups. Multivariate logistic regression analysis was used to identify potential risk factors associated with persistent hypercalcemia following parathyroidectomy. The proportion of patients with serum intact parathyroid hormone (PTH) level is greater than 65pg/ml was significantly high in the hypercalcemia group (40.9 vs. 7.7%). The proportion of patients who underwent less than subtotal parathyroidectomy was significantly high in the persistent hypercalcemia group (17.9 vs. 54.5%). Patients with a large remaining size of the preserved parathyroid gland (≥0.8cm) had a high incidence of persistent hypercalcemia (29.7 vs. 52.6%). In the multivariate logistic regression analysis, the drop rate of intact PTH is less than 88% on postoperative day 1 (odds ratio 10.3, 95% CI: 2.7-39.1, P =0.001) and the removal of less than or equal to 2 parathyroid glands (odds ratio 6.8, 95% CI: 1.8-26.7, P =0.001) were identified as risk factors for persistent hypercalcemia. The drop rate of intact PTH is less than 88% on postoperative day 1 and appropriate extent of surgery for controlling the autonomic function were independently associated with persistent hypercalcemia. Confirmation of parathyroid lesions through frozen section biopsy or intraoperative PTH monitoring can be helpful in preventing the inadvertent removal of a parathyroid gland and achieving normocalcemia after parathyroidectomy.

Intraoperative parathyroid hormone monitoring in parathyroidectomy for hyperparathyroidism: a protocol for a network meta-analysis of diagnostic test accuracy.

Intraoperative parathyroid hormone (iPTH) monitoring is standard-of-care in the surgical management of hyperparathyroidism. It involves real-time determination of circulating PTH levels to guide parathyroid gland excision. There exists several iPTH monitoring criteria, such as the Miami criteria, and a lack of standardization in the timing of post-parathyroid gland excision samples. We present a protocol of a systematic review and network meta-analysis of diagnostic test accuracy to identify the iPTH criteria and post-gland excision timepoint that best predicts surgical cure in hyperparathyroidism. The database search strategy will be developed in conjunction with a librarian specialist. We will perform a search of Medline (Ovid), EMBASE (Ovid), CINAHL, Cochrane Collaboration, and Web of Science from 1990-present. Studies will be eligible if they include adult patients diagnosed with hyperparathyroidism who undergo parathyroidectomy with iPTH monitoring. We will only include studies that report diagnostic test properties for iPTH criteria and/or post-excision sampling timepoints. All screening, full-text review, data extraction, and critical appraisal will be performed in duplicate. Critical appraisal will be performed using QUADAS-2 instrument. A descriptive analysis will present study and critical appraisal characteristics. We will perform evaluation of between-study heterogeneity using I2 and Cochrane Q and where applicable, we will perform sensitivity analysis. Our network meta-analysis will include Bayesian hierarchical framework with random effects using multiple models. Ethics approval is not required. This proposed systematic review will utilize a novel Bayesian network meta-analysis model to help standardize iPTH monitoring in hyperparathyroidism, thereby optimizing patient outcomes and healthcare expenditures.

Trends in using intraoperative parathyroid hormone monitoring during parathyroidectomy: Protocol and rationale for a cross-sectional survey study of North American surgeons.

Hyperparathyroidism is a common endocrine disorder that occurs secondary to abnormal parathyroid gland functioning. Depending on the type of hyperparathyroidism, surgical extirpation of hyperfunctioning parathyroid glands can be considered for disease cure. Intraoperative parathyroid hormone (IOPTH) monitoring improves outcomes in patients undergoing surgery for primary hyperparathyroidism, but studies are needed to characterize its institutional adoption and its role in surgery for secondary and tertiary hyperparathyroidism, as these entities can be difficult to cure. Hence, we will perform a cross-sectional survey study of surgeon rationale, operational details, and barriers associated with IOPTH monitoring adoption across North America. We will utilize a convenience sampling technique to distribute an online survey to head and neck surgeons and endocrine surgeons across North America. This survey will be distributed via email to three North American professional societies (i.e., Canadian Society for Otolaryngologists-Head and Neck Surgeons, American Head and Neck Society, and American Association of Endocrine Surgeons). The survey will consist of 30 multiple choice questions that are divided into three concepts: (1) participant demographics and training details, (2) details of surgical adjuncts during parathyroidectomy, and (3) barriers to adoption of IOPTH. Descriptive analyses and multiple logistic regression will be used to evaluate the impact of demographic, institutional, and training variables on the use of IOPTH monitoring in surgery for all types of hyperparathyroidism and barriers to IOPTH monitoring adoption. Ethics approval was obtained by the Hamilton Integrated Research Ethics Board (2024-17173-GRA). These findings will characterize surgeon and institutional practices with regards to IOPTH monitoring during parathyroid surgery and will inform future trials aimed to optimize the use of IOPTH monitoring in secondary and tertiary hyperparathyroidism.

Neonatal Severe Hyperparathyroidism: A Case Report

Background: Neonatal severe hyperparathyroidism is an extremely rare condition that presents in the first few months of life. Recognition at the early stage followed by prompt surgical intervention are of vital importance for survival. Hypotonia, respiratory distress, lethargy and delay in growth and development occur in association with the elevated serum parathormone levels and hypercalcemia. Definitive therapy involves total parathyroidectomy. Case Description: We are presenting a case with Neonatal severe hyperparathyroidism, who underwent total parathyroidectomy. The patient had been followed up with medical therapy until. Parathormone levels rapidly declined following total parathyroidectomy and the patient was discharged with full recovery. Literature Review: Sestamibi scintigraphy might fail to show an ectopic parathyroid gland. In such conditions, on table confirmation of parathyroid glands by frozen section and Intraoperative parathormone monitoring is vital at this point. Persistently elevated parathormone levels might suggest a remnant parathyroid tissue at the surgical site or an ectopic parathyroid gland that should be excised. Clinical Relavance: Neonatal severe hyperparathyroidism is a life-threatening disease. In the present case surgery performed at the early is life-saving due to the failure of medical therapy to control the disease.

A >50% Intraoperative Parathyroid Hormone Level Decrease Into Normal Reference Range Predicts Complete Excision of Malignancy in Patients With Parathyroid Carcinoma

IntroductionThe mainstay of successful treatment for parathyroid carcinoma remains complete surgical excision. Although intraoperative parathyroid hormone (ioPTH) monitoring is a useful adjunct during parathyroidectomy for benign primary hyperparathyroidism, its utility for parathyroid carcinoma remains unclear. MethodsA retrospective review of 796 patients who underwent parathyroidectomy with ioPTH monitoring for primary hyperparathyroidism revealed 13 patients with parathyroid carcinoma on final pathology from two academic institutions. A systematic review yielded 5 additional parathyroid carcinoma patients. Complete excision of malignancy, or operative success (eucalcemia ≥6 mo. after parathyroidectomy); operative failure (persistent hypercalcemia <6 mo. after parathyroidectomy); and perioperative complications were evaluated. Comparison of the >50% ioPTH decrease alone to >50% ioPTH decrease into normal reference range was analyzed using Chi-squared, Kolmogorov–Smirnov, Kruskal–Wallis tests. ResultsAll 18 parathyroid carcinoma patients achieved a >50% ioPTH decrease, and 14 patients also had a final ioPTH level decrease into normal reference range. 93% of patients who met normal parathyroid hormone reference range had operative success, whereas only two of the four (50%) patients with parathyroid carcinoma with a >50% ioPTH decrease alone demonstrated operative success. ConclusionsParathyroidectomy guided by a >50% ioPTH decrease into normal reference range may better predict complete excision of malignant tissue in patients with parathyroid carcinoma compared to >50% ioPTH decrease alone. IoPTH monitoring should be used in conjunction with clinical judgment and complete en bloc resection for optimal treatment and success.

Minimally Invasive Parathyroidectomy using Intraoperative Ultrasonography in Parathyroid Adenoma Patients with a History of Total Thyroidectomy

A 65-year-old patient who underwent total thyroidectomy 10 years ago was suspected of having a parathyroid adenoma, and minimally invasive parathyroidectomy was planned. Preoperative ultrasonography(USG) and 99mTc MIBI scan indicated a left lower parathyroid lesion. In the first operation, intraoperative parathyroid hormone monitoring (IOPTH) was not possible due to hospital circumstances. Although no adenomatous lesion was found in the expected surgical field, surgery was completed after removing lesions around the left lower parathyroid gland. However, post-surgery, parathyroid hormone did not decrease at all, so a second operation was performed with IOPTH preparation. In the second operation, intraoperative ultrasonography was performed, and a suspected adenoma lesion was removed from the left upper lesion. He has been under follow-up for 3 years without complications. Surgeon-peformed intraoperative USG and preoperative scintigraphy had advantages in determining the localization of parathyroid lesion even withiout IOPTH.

Therapeutic and diagnostic algorithm for preoperative prediction of sporadic multigland parathyroid disease

BACKGROUND: Primary hyperparathyroidism (PHPT) is a common endocrinological disease that is characterized by autonomic increased synthesis of parathyroid hormone (PTH) with elevated or upper-normal levels of blood calcium [1]. In 80–85% of cases, the cause of sporadic PHPT is an adenoma of one parathyroid gland (PTG) (sigle-gland parathyroid disease), in 20–25% — a lesion of a larger number of PTGs (hyperplasia of all glands or double adenomas — multigland parathyroid disease) [2]. The complexity of clinical and laboratory prediction, low sensitivity of imaging methods, poor assessment of the radicalness of the operation by intraoperative monitoring of intact PTH (IMiPTH) are the components of the problem of multiple lesions in PHPT. Therefore, the improvement of existing and the development of new methods for diagnosing and treating this variant of the disease are urgent tasks of modern endocrine surgery.AIM: To develop an algorithm for the diagnosis and treatment of PHPT, aimed at preoperative detection of multigland parathyroid disease.MATERIALS AND METHODS: The study was based on a study of a continuous sample of 208 patients, of which 34 with multigland parathyroid disease in PHPT, 95 with single-gland parathyroid disease in PHPT, 69 with secondary hyperparathyroidism on renal replacement therapy (RRT) with hemodialysis, and 10 with tertiary hyperparathyroidism on RRT of LT. The work was performed on the basis of clinical, laboratory, instrumental, morphological and immunohistochemical studies. The nature of the expression of the calcium-sensitive receptor and the vitamin D receptor in the studied groups was studied as a pathogenetic substantiation of the proposed algorithm [3]. Based on the study of clinical and laboratory parameters and the results of preoperative imaging methods, predictors of multigland parathyroid disease in PHPT [4,5] were established, and a method for differential diagnosis of PTG lesions in PHPT was developed [6]. In addition, the results of surgical treatment of patients with multiple PTG lesions in various clinical variants of hyperparathyroidism were studied [7]. RESULTS: The proposed algorithm is used when the diagnosis of PHPT is already established and there are indications for surgical treatment. First of all, the level of GFR (CKD-EPI) is assessed in conjunction with the results of the “gold standard” preoperative imaging methods (ultrasound and scintigraphy), with an assessment of the number of localized increased PTG and the consistency of the results of preoperative methods.At a GFR level of more than 73 ml/min/1.73 m2, an increase of only 1 PTG according to the results of 2 imaging methods, provided that they are consistent, the PHPT variant is defined as a sigle-gland parathyroid disease. If there is an inconsistency between the 2 methods of preoperative imaging, we recommend calculating the scores according to the differential diagnosis scale for multiple lesions in PHPT [6]. At a GFR level of less than 73 ml/min/1.73 m2, an increase of &gt;1 PTG according to the results of 2 imaging methods, we recommend calculating points according to the proposed scale [6].With the established variant of PHPT — sigle-gland parathyroid disease, the patient undergoes selective parathyroidectomy (PTE) with IMiPTH. When iPTH drops to reference values, the test is considered positive, and the operation ends there. If the test result is negative, a second test is required after 10 minutes. In the event that the repeated test is also negative, then the patient is shown a bilateral neck exploration (BNE) in accordance with the tactics for multigland parathyroid disease (see below).With the established variant of PHPT — multigland parathyroid disease, the following tactics are used:BNE with obligatory exploration of all four PTGs;Macroscopic assessment of the PTG found.When making a decision about 2 pathologically changed enlarged PTG, and 2 others are intact and not enlarged, a double PTE with IMiPTH is performed. If after the removal of 2 pathologically altered PTGs, the IMiPTH test is negative, then a second one is necessary after 10 minutes. In the event that the repeated test is negative, then from the 2 recognized intact ones, the least altered is determined and the scope of the operation is expanded to subtotal PTE (3.5 PTG), leaving ½ of the least altered PTG. The operation ends here.When deciding that 3 or more PTG are pathologically changed and enlarged, a subtotal PTE with IMiPTH is performed. In case of a negative IMiPTH test, the places of possible ectopic location of the PTG are examined: thyrothymic ligaments, upper thymus horns, fatty tissue along the carotid arteries. If there are no ectopically located PTGs in the indicated places, the operation is completed.CONCLUSION: The proposed treatment and diagnostic algorithm is pathogenetically substantiated, aimed at preoperative detection of multiple PTG lesions in PHPT and will improve the quality of life of this group of patients by reducing the persistence of the disease.

SAT193 Double Trouble: A Case of Ipsilateral Double Parathyroid Adenoma

Abstract Disclosure: J.P. Suelto: None. G.D. Wassmer: None. Background: Eighty percent of the cases of Primary Hyperparathyroidism is caused by a single adenoma and only about 15% are multiglandular adenoma. Parathyroid imaging like Sestamibi is less sensitive in detecting multiglandular disease. Clinical Case: A 63 year-old female presented with intermittent left lower back pain for 7 years. There was no joint pain, weakness, urinary symptoms, constipation and abdominal pain. In 2019, due to persistence of left back pain, abdominal ultrasound done showed a right non-obstructing nephrolithiasis. Ionized and total calcium were elevated at 1.53 meq/L (NV 1.12-1.32 meq/L) and 11.35 ng/dl (NV 8.42-10.23 ng/dl) respectively with normal creatinine, phosphorus and albumin. PTH was elevated at 116.6 pg/ml (NV 10-65 pg/ml). Primary Hyperparathyroidism probably secondary to parathyroid adenoma was considered. Thyroid ultrasound showed right thyroid cyst but no enlarged parathyroid gland. Parathyroid imaging using Dual Isotope Subtraction Method neither showed evidence of adenoma. Patient was advised parathyroidectomy but did not consent hence started on Cinacalcet. In 2021, ionized calcium was still elevated to 1.58 meq/L with elevated PTH 151 pg/ml and low Vitamin D level 22.76 ng/ml (&amp;gt;30 ng/mL). Patient was given Vitamin D3 2000 IU daily and Cinacalcet was up-titrated to 60mg daily. Sestamibi/SPECT CT showed faint focus of radioactivity in the right thyroidal bed area suspicious for parathyroid adenoma or hyperplasia. She then agreed to have parathyroidectomy. There was no decrease in PTH after removal of the right inferior parathyroid gland (measuring 1.8x0.6x0.6cm, weighs 500mg), hence re-exploration was done. It was only after the removal of the right superior parathyroid gland (measuring 2.8x0.9x0.7cm, weighs 1 gram) when the 5 and 10 minute post excision PTH decreased to 123.91 and 76.01 pg/ml respectively from preincision PTH of 407.19 pg/ml. Histopathology showed Parathyroid adenoma of right inferior and superior parathyroid glands. No further evidence of hypercalcemia was noted at 6-month follow-up. Conclusion: Double adenoma is reported in 2% to 12% of patients with primary hyperparathyroidism. This occurs predominantly as bilateral superior in 45% and on same side of the neck in 18%. Sestamibi scanning is poor in the presence of multiglandular disease. It was observed that the presence of oxyphil cells may cause longer sestamibi retention in parathyroid tissues. Given the same amount of oxyphil cells in ipsilateral adenomas, the tracer may be distributed hence faintly seen on imaging. Addition of SPECT/CT/4D CT may improve the anatomical localization. Another reason for false negative imaging in this patient can be due to use of Cinacalcet which may decrease scintigraphy uptake of parathyroid adenoma. The combination of preoperative imaging localization and intraoperative PTH monitoring permits successful surgical outcome. Presentation: Saturday, June 17, 2023

Intraoperative Parathyroid Hormone Monitoring In Normohormonal Primary Hyperparathyroidism: How Low Do You Go?

The primary goal of this study was to determine in patients with normohormonal primary hyperparathyroidism (NHHPT) what percent reduction in post-excision intraoperative parathyroid hormone (IOPTH) from baseline would yield a rate of cure comparable to that in patients with classical primary hyperparathyroidism (PHPT). This is a retrospective cohort study of patients who underwent parathyroidectomy between July 2013 and February 2020. Demographic data, preoperative, intraoperative, and postoperative metrics were collected. Patients with NHHPT were compared to those with classical PHPT. Subgroup analyses were performed. Of the 496 patients included in the study, 66 (13.3%) were of the normohormonal variant based on preoperative intact parathyroid hormone (PTH) levels and 28 (5.6%) based on baseline IOPTH levels. The cure rates in the two normohormonal groups were not significantly different from their classical counterparts (98.4% and 100.0% vs. 97.1%, p = 1.000). The median percent decline in post-excision IOPTH from baseline that achieved cure in the normohormonal groups were 82.6% and 80.4% compared to their respective controls at 87.3%, p = 0.011 and p = 0.001. Although the rate of multiglandular disease was higher in one of the normohormonal variant groups, this difference was due to a higher rate of double adenomas, not four-gland hyperplasia. Patients with NHHPT undergoing parathyroidectomy can expect cure rates similar to that in patients with classical PHPT. The results of this study indicate that achieving an 80% drop or more in IOPTH levels predicts a high likelihood of cure. This is true irrespective of whether the patient is deemed normohormonal based on preoperative or intraoperative testing. 3 Laryngoscope, 134:2480-2484, 2024.

Diagnostic Value of Four-Dimensional Dynamic Computed Tomography for Primary Hyperparathyroidism in Patients with Low Baseline Parathyroid Hormone Levels.

Low baseline levels of parathyroid hormone (PTH) are associated with a higher rate of multiglandular disease, lower localization rates of preoperative imaging modalities, and a higher rate of unsuccessful minimally invasive parathyroidectomies. The objective of this study is to assess the diagnostic value of four-dimensional dynamic computed tomography (4D-CT) in localizing primary hyperparathyroidism (pHPT) in patients with low baseline PTH levels, compared to patients with high baseline PTH levels. Patients with pHPT who received a 4D-CT scan as part of their standard diagnostic evaluation were divided into two groups based on the following criteria: (1) preoperative PTH levels less than 100 pg/mL and (2) patients with preoperative PTH levels greater than 100 pg/mL. All patients underwent parathyroidectomy based on 4D-CT findings, with intraoperative parathyroid hormone monitoring. The lesion-based sensitivity of 4D-CT was 88% in patients with low baseline PTH levels and 94.7% in patients with high baseline PTH levels (p = 0.33). However, the success rate of image-guided resection based on 4D-CT findings was 71.4% in the low baseline PTH group compared to 90.6% in the high baseline PTH group (p = 0.06). Our study demonstrated that 4D-CT has a high lesion-based sensitivity in patients with pHPT and low baseline PTH levels but led to a relatively low rate of successful image-guided resection in patients with low baseline PTH levels. Therefore, it is important to exercise increased caution during 4D-CT-guided surgical exploration of patients with low baseline PTH levels to ensure successful surgical resection of all parathyroid lesions.

The role of autofluorescence and Indocyanine green (ICG) in Endocrine Surgery

Parathyroid preservation during total thyroidectomy is crucial in preventing postoperative hypoparathyroidism. The use of intraoperative parathyroid hormone monitoring has been shown to reduce the incidence of hypoparathyroidism. However, this method has limitations, and alternative techniques such as autofluorescence and ICG angiography have emerged as potential options for parathyroid preservation. The use of ICG angiography and near-infrared autofluorescence has shown promise in improving parathyroid gland preservation and reducing the risk of postoperative hypocalcaemia and hypoparathyroidism. The combination of autofluorescence and ICG angiography has also been found to be useful in identifying parathyroid glands in challenging cases, such as reoperations for thyroid or parathyroid diseases. However, further studies are needed to establish its long-term safety and efficacy and to address the limitations of its implementation in clinical practice.

Operative success is achieved regardless of ioPTH criterion used during focused parathyroidectomy for sporadic primary hyperparathyroidism

BackgroundFocused parathyroidectomy (F-PTX) guided by intraoperative parathormone (ioPTH) monitoring may result in higher operative failure rates from missed multiglandular disease (MGD) in patients with sporadic primary hyperparathyroidism (spHPT) when ioPTH levels do not reach normal range. MethodsA retrospective review included 690 patients with spHPT who underwent F-PTX and ioPTH monitoring were divided into 2 groups: >50% ioPTH decrease to normal range, and >50% ioPTH decrease to above normal range. Operative success, recurrence, bilateral/unilateral neck exploration (BNE/UNE), MGD were evaluated. Results533 patients demonstrated >50% ioPTH decrease to normal range, and 157 patients >50% ioPTH decrease to above normal range. There were no differences in operative success 99% vs. 97%, recurrence 2.5% vs. 5%, BNE 12% vs. 11%, UNE 4% vs. 5%, or MGD 4% vs. 4%, (p > 0.05) with 46 months mean follow-up. ConclusionsThere were no differences in operative success, failure, BNE, UNE or MGD regardless of ioPTH criterion used for F-PTX.

Submandibular Ectopic Parathyroid Adenoma: A Case Report.

Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterized by hypercalcemia and elevated or abnormally normal parathyroid hormone (PTH) levels, due to excessive secretion of PTH by 1 or more parathyroid glands. In this report, we discuss the diagnostic and therapeutic challenges posed by ectopic parathyroid adenomas, a rare but atypical presentation of PHPT. We present the case of a 36-year-old female with PHPT due to an ectopic parathyroid adenoma located in the submandibular region. The patient presented with bone pain and was initially evaluated with routine imaging studies, which were negative. [18F] F-choline positron emission tomography (PET)/Computed tomography revealed the ectopic adenoma, leading to successful surgical management. Ectopic parathyroid adenomas are rare but can occur in various locations, and functional imaging modalities such as choline PET can aid in their detection. Surgical resection remains the definitive treatment for parathyroid adenomas, with intraoperative PTH monitoring guiding the extent of resection. Proper evaluation and management of PHPT is essential to avoid significant morbidity. Our case adds to the growing body of literature on the importance of considering ectopic locations of parathyroid adenomas in patients with PHPT.

A-310 18F-FLUOROCHOLINE-PET/CT IS THE BETTER TOOL TO LOCALISE “NEGATIVE” PARATHYROID ADENOMAS – INTRAOPERATIVE CORRELATION AND 12 MONTH POSTOPERATIVE RESULTS

Abstract Background To characterise the diagnostic performance of 18F-Fluorocholine PET/CT (FCH-PET/CT) to localise parathyroid adenomas (PA) in primary hyperparathyroidism (pHPT) when ultrasound (US) and MIBI-Scan (MS) failed - intraoperative correlation and one year follow up. Methods Beginning in 07/2017 FCH-PET/CT was employed in patients with proven pHPT in whom US and MS delivered either incongruent or negative findings. All patients were offered cervical explorations with intraoperative PTH-monitoring (IO-PTH) and followed for 12 months postoperatively. Imaging results were correlated to operative findings and histopathologic reports and to short term biochemical outcome as well as one-year postoperative follow-up data. Results From 07/2017 to 11/2022, 1085 patients were operated for pHPT. In this period, 215 FCH-PET/CT were performed suggesting PA(s) in 176, 6 false positive, and 33 false negative (sensitivity 84.2%, PPV 96.7%). Of the 95 cases were US and MIBI both gave negative results, FCH-PET/CT accurately localised PA(s) to the respective side of the neck in all the 72 FEC-PET-positive cases (global sensitivity of 75.8%); and was negative in 23 (24.2%). In the 12-month postoperative follow up (currently matched by 61/95) there was no biochemical persistent disease. However, 3 patients exhibited PTH or calcium at the upper limit of norme, thus, a recurrence cannot be reliably excluded so far. Conclusion FCH-PET/CT allows for planned unilateral and focused as opposed to bilateral explorations, especially when preoperative parathyroid localisation with US and MiBI fails. We, therefore, suggest FCH-PET/CT as the preferred tool for the localisation of the “negative” PA.