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

Intraoperative Parathyroid Hormone Kinetics are Variable: An In-Vivo Analysis

OBJECTIVES

Intraoperative parathyroid hormone (IOPTH) monitoring has become routine in parathyroid surgery to facilitate less invasive techniques to treat hyperparathyroidism. Despite this, little is known about in vivo IOPTH kinetics, which can greatly affect the reliability of its interpretation.

METHODS

A prospective cohort of patients undergoing routine parathyroidectomy was studied. During each case, IOPTH was measured frequently, during all key perioperative events. Qualitative, univariate, and multivariate analysis was performed to better understand the patterns of in vivo IOPTH kinetics.

RESULTS

The IOPTH increased from preoperative baseline in every case, but some patients had a rapid spike after gland manipulation while others had a more gradual increase. The IOPTH peak occurred prior to excision in almost every case. The IOPTH began to fall prior to excision, typically returning to preoperative baseline levels just before excision. The average in vivo half-life of parathyroid hormone (PTH) was 5.2 minutes.

CONCLUSION

There is substantial variation in the in vivo IOPTH kinetics and more research is needed to understand predictors of kinetic patterns and PTH half-life during parathyroidectomy.

Findings of pilot study following the implementation of point of care intraoperative PTH assay using whole blood during surgery for primary hyperparathyroidism

Objective

To report findings of pilot study using a novel point of care (POC) intraoperative parathyroid hormone (IOPTH) assay for parathyroid hormone (PTH) using whole blood during surgery for primary hyperparathyroidism (PHPT).

Methods

Patients undergoing surgery for primary hyperparathyroidism from March to November 2022 where intraoperative PTH assay was performed using the NBCL CONNECT IOPTH and the laboratory PTH assay were included (group 1). The biochemistry results were reviewed to determine concordance between NBCL and lab PTH values and diagnostic test parameters of the NBCL CONNECT assay. 'In-theatre' times were then compared with a historical cohort (group 2) where the lab-based IOPTH assay alone was used.

Results

Of the 141 paired samples in group I, correlation between NBCL and the lab assay was high (rho=0.82; p<0.001). PTH levels using the NBCL assay dropped satisfactorily (>50% of the basal or 0 min sample; whichever was lower - i.e. positive test) in 23 patients; giving a positive predictive value of 100%. Of the 9 patients that did not demonstrate a drop, two were true negative (negative predictive value of 22%) leading to cure after excision of another gland. Group 1 (150 mins) had a significantly shorter 'in-theatre' time compared to group 2 (167 mins) (p=0.007); despite much higher use of near infra-red autofluorescence (NIRAF) (72% vs 11.6% in group I and 2 respectively).

Conclusion

The NBCL CONNECT POC IOPTH assay gives comparable results to lab based PTH assays and can be performed without need for a centrifuge or qualified technicians. Surgeons, however, need to be aware of the potential for false-negative results.

Parathyroidectomy for primary hyperparathyroidism: A retrospective analysis of localization, surgical characteristics, and treatment outcomes

OBJECTIVE

To evaluate parathyroidectomy for primary hyperparathyroidism (PHPT) regarding localization, surgical characteristics, and treatment outcomes.

METHODS

Seventy-eight patients who underwent parathyroidectomy for PHPT were retrospectively reviewed. The results were analyzed according to intraoperative localization technique (IOLT), intraoperative parathyroid hormone (IOPTH) monitoring, and intraoperative nerve monitoring (IONM). The localization accuracy of ultrasonography (US), computed tomography (CT), and single-photon emission computed tomography (SPECT)-CT with sestamibi Tc99m was evaluated.

RESULTS

Parathyroidectomy was successfully completed in all 78 patients, achieving 100% surgical cure. For 60 patients with IOPTH monitoring, 10-min IOPTH decreased >50% from baseline in 57 (95.0%), and they achieved surgical cure. In the remaining three (5.0%) patients with ≤50% decrease in 10-min IOPTH, 20-min IOPTH decreased >50% from baseline in two (3.3%) patients, achieving surgical cure without additional neck exploration. There were no differences in surgical cure and complications as a function of IOLT use or IOPTH monitoring. Operating time was significantly shorter with IOLT and IOPTH monitoring than without (IOLT: 70.9 min vs. 88.0 min, p = 0.013; IOPTH: 74.9 min vs. 91.9 min, p = 0.037). All 78 patients had adenoma including one patient with a double adenoma. Vocal cord paralysis was not observed in our series, regardless of IONM. US, CT, and SPECT-CT localized the pathological parathyroid gland accurately in 88.1%, 85.5%, and 86.8% of patients, respectively (p = 0.894).

CONCLUSION

The surgical outcomes of parathyroidectomy for PHPT were excellent regardless of IOLT and IOPTH monitoring. However, these techniques can maximize the performance of parathyroid surgery by reducing operating time and rescuing challenging cases.

Primary Hyperparathyroidism: Is Image Localization Alone Sufficient to Ensure Long-Term Cure in Unifocal Disease?

INTRODUCTION

Advances in imaging have facilitated precise preoperative localization and focused resection of hyperfunctional parathyroids in primary hyperparathyroidism (PHPT). Combining imaging techniques or a "dual" approach, when concordant, improves adenoma-localizing accuracy above individual modalities. This study sought to assess biochemical cure and failure rates (persistence or recurrence) of surgery directed by dual imaging alone in PHPT.

METHODOLOGY

This observational, single-center analysis comprised 31 patients diagnosed with PHPT and imaged with both ultrasound (USG) of the neck and sestamibi scintigraphy. The extent of surgery was based solely on inter-modality concurrence for adenoma localization; imaging-concordant patients underwent focused parathyroidectomy, whereas discordant patients necessitated neck exploration (with extent altered according to scintigraphic lesion lateralization). No intraoperative localizing adjuncts were used.

RESULTS

Twenty-three patients had concordant imaging, of which 19 underwent focused exploration, with sensitivity and positive predictive value (PPV) for dual imaging of 100% and 95.7%, respectively. The overall sensitivity and PPV were 92.9% and 89.7% for USG alone and 100% and 93.6% for scintigraphy, respectively. The mean age and prevalence of thyroid disease were significantly higher in the discordant group. All patients achieved postoperative normocalcemia. There were no cases of persistent or recurrent hyperparathyroidism on follow-up.

CONCLUSIONS

In the imaging-concordant setting, focused surgery may be safely performed with the omission of other adjuncts for localization. Older age and concomitant thyroid pathology predispose to discordant imaging and are risk factors for surgical failure when attempting an image-directed approach. Neck exploration is an alternative in these patients with excellent cure rates and acceptable morbidity.

Determinants and clinical significance of negative scintigraphic findings in primary hyperparathyroidism: a retrospective observational study

AIM

In patients with recurrent primary hyperparathyroidism (pHPT) or preceding thyroid operation, scintigraphic localization of the pathological parathyroid gland is sometimes unsuccessful. Reason for diagnostic failure, and its clinical relevance is poorly understood.

METHODS

This retrospective observational study in patients suffering from a pHPT evaluated independent predictors of a negative preoperative scintigraphy (SC) result, and its relevance for intraoperative outcome using logistic regression analysis.

RESULTS

Among 86 pHPT patients scheduled for parathyroid operation, 63 (73%) had a history of a preceding thyroid or parathyroid operation. Preoperative SC could not identify an adenoma in 30 patients (34.9%), and in 12 patients (14.0%), the surgeon was subsequently unable to localize abnormal parathyroid tissue. Preoperative parathyroid hormone concentration was the only significant independent predictor of a negative SC finding (non-linear and indirect association). Independent from surgical history, an unsuccessful intraoperative focus localization was exclusively predicted by preoperative ultrasonographic (US) and SC findings (OR per diagnostic category 2.98; 95%-CI 1.03-8.58, p=0.043, and OR 2.26; 95%-CI: 1.10-4.63, p=0.027, respectively). Compared to exclusive US, however, the combination of SC and US significantly increased the sensitivity and predictive power to identify patients at a high risk for a complicated surgical procedure.

CONCLUSION

In patients before parathyroidectomy, a low preoperative parathyroid hormone concentration is significantly associated with a high likelihood for a negative SC finding. Combining US with SC before operation significantly increases the chance to identify patients prone to negative intraoperative findings.

Parathyroid venous sampling for the preoperative localisation of parathyroid adenoma in patients with primary hyperparathyroidism

Preoperative localisation studies are essential for parathyroidectomy in patients with primary hyperparathyroidism. If the location of abnormal parathyroid glands cannot be identified through non-invasive studies, parathyroid venous sampling (PVS) may be employed. In this study, we evaluated the utility of preoperative PVS in parathyroid surgery. Patients with primary hyperparathyroidism who underwent preoperative PVS at Severance Hospital between January 2015 and June 2020 were identified. Patients for whom the results of non-invasive imaging studies were inconsistent or negative underwent PVS. The results of PVS were compared with operative findings and pathologic results. For 14 patients, the results of preoperative ultrasonography and ^99mTc-sestamibi single-photon emission computed tomography (SPECT) were negative; for 20 patients, either the result of only one test was positive, or the results of the two tests were inconsistent. With respect to the lateralisation of diseased adenoma, the results of PVS and pathological examination were inconsistent only for one patient in either group (total: 2/34 patients). This study showed that PVS could be used effectively for preoperative localisation in patients with primary hyperparathyroidism in whom the location of diseased parathyroid glands cannot be determined through non-invasive image studies.

Intraoperative assessment of parathyroid pathology in sporadic primary hyperparathyroidism: An institutional experience

Intraoperative consultation for assessment of parathyroid tissue is a controversial area of endocrine pathology. This assessment often follows historical institutional and individual surgical practitioner practices rather than documented utility data and adjuvant intraoperative testing data, including intraoperative parathyroid hormone level testing by clinical pathologists and the use of Oil Red O vital stain on frozen tissue sections by anatomic pathologists, as a means of conferring etiology of parathyroid disease. The American Association of Endocrine Surgeons (AAES), in 2016, proposed guidelines for the management of primary hyperparathyroidism, including recommendations for intraoperative consultation, recommending against the use of intraoperative frozen section to determine parathyroid functional status but in support for its use for parathyroid identification. In this series, we review a one-year, retrospective cohort of consecutive parathyroid surgeries at Massachusetts General Hospital, including over 200 cases meeting inclusion criteria for which primary hyperparathyroidism was the indication for surgery, discussing outcomes, compliance with AAES guidelines, and overall utility of intraoperative consultation and adjuvant testing.

A mini-invasive approach is feasible in patients with primary hyperparathyroidism and discordant or negative localisation studies

Preoperative localisation of pathological glands in patients with primary hyperparathyroidism (PHP) is the mainstay for mini-invasive parathyroidectomy. Nevertheless, a not negligible number of patients presents discordant or negative neck ultrasound (US) and ^99mTc-Sestamibi (MIBI) scan. The aim of this study was to assess if a mini-invasive approach is feasible in this kind of patients. In this retrospective study were included patients that underwent parathyroidectomy for PHP. Patients were divided into two groups according to concordance of US and MIBI scan results. 242 patients were included: 183 had concordant preoperative studies, and 59 had discordant or negative studies. A mini-invasive approach was possible in 42 (72.9%) patients with unclear preoperative studies, whereas 12 (20.3%) additional patients required conversion to BNE. The incidence of persistent PHP was higher in patients with unclear preoperative studies (8.5% vs 2.7%), but this difference did not reach a statistical significance (p = 0.121). In patients with unclear preoperative studies, a negative result of intraoperative PTH allowed to avoid a persistent disease in 12 patients, while in 3 cases led to an unnecessary additional exploration. In patients with discordant preoperative studies a mini-invasive approach is feasible; in this setting, the use of intraoperative PTH is mandatory to reduce the incidence of persistent PHP.

Surgical management of primary hyperparathyroidism during pregnancy: a systematic review of the literature

OBJECTIVE

Gestational primary hyperparathyroidism (PHPT) is an endocrinological disorder with serious outcomes for both women and neonates. The aim of our study was to present the current evidence concerning the perioperative outcomes of pregnant women with PHPT who underwent parathyroidectomy during pregnancy.

METHODS

A meticulous systematic review of the literature published before February 2020 and all studies which presented perioperative and pregnancy outcomes off pregnant women who underwent parathyroidectomy for PHPT, were included.

RESULTS

A total of 53 were finally included, which reported 92 pregnant women who had parathyroidectomy during their pregnancy. A total of 46 patients were hospitalized due to significant complications of PHPT before their parathyroidectomy. With regards to surgical approach, 52.2% of patients underwent minimally invasive parathyroidectomy (MIP), while bilateral neck exploration (BNE) was 41.3% of cases. Only 4 women was not cured, whereas transient hypocalcemia was occurred in 18 patients. All cases proceeded to deliveries of healthy neonates, after their parathyroidectomy.

CONCLUSIONS

Parathyroidectomy during pregnancy is a safe and effective treatment option with minimum complications and probably should be considered as the treatment of choice in specific group of pregnant women with PHPT.

The role of Rapid Intraoperative Parathyroid Hormone (ioPTH) assay in determining outcome of parathyroidectomy in primary hyperparathyroidism: A systematic review and meta-analysis

BACKGROUND

Primary hyperparathyroidism (PHPT) is a common endocrine disorder. In the last few decades, the introduction of Rapid Intraoperative Parathyroid Hormone (ioPTH) monitoring has allowed to ensurance of the excision of all hyperfunctioning parathyroid tissues, reducing the risks of persistent and recurrent PHPT. However, the use of ioPTH is still debated among endocrine surgeons.

MATERIAL AND METHODS

The objective of this systematic review and meta-analysis was to assess if ioPTH monitoring is able to reduce the incidence of persistent or recurrent PHPT. A systematic literature search was performed using PubMed, Scopus, ISI-Web of Science and Cochrane Library Database. Prospective and retrospective studies addressing the efficacy of ioPTH monitoring were included in the systematic review and meta-analysis. The random-effects model was assumed to account for different sources of variation among studies. The overall effect size was computed through the inverse variance method. Heterogeneity across studies, possible outlier studies, and publication bias were evaluated.

RESULTS

A total of 28 studies with 13,323 patients were included in the quantitative analysis. The incidence of operative failure was 3.2% in the case group and 5.8% in the control group. After excluding three outlier studies, the quantitative analysis revealed that ioPTH reduced significantly the incidence of postoperative persistent or recurrent PHPT. (Risk Difference = -0.02; CI = -0.03, -0.01; p < 0.001). There was no evidence of heterogeneity among the studies (Q = 19.92, p = 0.70; I² = 0%). The analysis of several continuous moderators revealed that the effectiveness of ioPTH was larger in studies with lower preoperative serum calcium values and higher incidences of multiple gland disease.

CONCLUSION

ioPTH monitoring is effective in reducing the incidence of persistent and recurrent PHPT. Its routine use should be suggested in the next guidelines regarding management of PHPT.

Minimally invasive video-assisted parathyroidectomy (MIVAP) without intraoperative PTH determination

BACKGROUND

Minimally invasive video-assisted parathyroidectomy (MIVAP) has become a standard approach to primary hyperparathyroidism (pHPT) since described. Although intraoperative parathyroid hormone assay (IOPTH) has been generalized as a complementary technique to MIVAP, its actual impact on the surgical success of this technique is not without controversy. The aim of this study was to describe our results in the management of pHPT with successful preoperative localization, by MIVAP technique, without IOPTH determination, confirming in a larger series our preliminary results.

METHODS

A retrospective descriptive study was conducted in pHPT patients treated by MIVAP with no IOPTH determination in a tertiary hospital between 2007 and 2019.

RESULTS

A total of 167 patients were included in the study. Biochemical cure was achieved in 96.4%, and 94.1% did not present any surgical complication. The mean duration of surgery was 61 min, and the mean length of hospital stay was 1.8 days CONCLUSIONS: In case of positive preoperative localization studies, MIVAP is a safe and effective technique for the surgical treatment of pHPT due to a parathyroid adenoma, regardless of IOPTH determination, with a success rate > 95% and a low complication rate.

Selection of parathyroidectomy methods for primary hyperparathyroidism according to concordance between ultrasonography and MIBI scan results

Background

Determination of appropriate operative methods for primary hyperparathyroidism (PHPT) is difficult when localisation results are discordant between imaging studies. The aim of this study was to compare the efficacy of focused parathyroidectomy (FP) and bilateral neck exploration (BNE) according to the concordance in localisation results.

Method

One hundred and ninety-one patients who underwent a PHPT operation at Asan Medical Center between 2000 and 2010 were divided into two groups according to the concordance in findings between neck ultrasonography (USG) and sestamibi (MIBI) scan. Differences in clinicopathological features and surgical outcomes between the concordant (n=137) and discordant (n=54) groups were analysed.

Results

FP and BNE did not show significant differences in postoperative persistent hyperparathyroidism rates. Although intraoperative parathyroid hormone (IOPTH) monitoring was not performed in this study, the cure rates of PHPT using only USG and MIBI scans were satisfactorily high, at 98.5% in the concordant group and 96.3% in the discordant group. The cure rates of FP and Unilateral exploration in single-negative USG and MIBI scans were 100%. Multiple lesions and hyperplasia were more common in the discordant group.

Conclusions

In cases where it is difficult to apply IOPTH, FP without IOPTH is feasible in patients showing concordant or single-negative detection on USG and MIBI scans, whereas BNE is recommended in cases of discordance or double-negative results on imaging studies, to prevent recurrence or persistent disease. Appropriate selection of parathyroidectomy methods according to the concordance in USG and MIBI scans might produce good results without any difference in recurrence.

Benefit of diverse surgical approach on short-term outcomes of MEN1-related hyperparathyroidism

Surgical excision is the preferred treatment for multiple endocrine neoplasia type 1 (MEN1)-related primary hyperparathyroidism (PHPT), although controversy regarding the surgical strategy exists. We retrospectively investigated the short-term outcomes of PHPT by various surgical extents. Thirty-three patients who underwent parathyroidectomy due to MEN1-related PHPT at Yonsei Severance Hospital between 2005 and 2018 were included (age [mean ± SD], 43.4 ± 14.1 [range, 23–81] years). Total parathyroidectomy with auto-transplantation to the forearm (TPX) was the most common surgical method (17/33), followed by less-than-subtotal parathyroidectomy (LPX; 12/33) and subtotal parathyroidectomy (SPX; 4/33). There was no postoperative persistent hyperparathyroidism. Recurrence was high in the LPX group without significance (1 in TPX, 2 in SPX, and 3 in LPX, p = 0.076). Permanent and transient hypoparathyroidism were more common in TPX (n = 6/17, 35.3%, p = 0.031; n = 4/17, 23.5%, p = 0.154, respectively). Parathyroid venous sampling (PVS) was introduced in 2013 for preoperative localisation of hyperparathyroidism at our hospital; nine among 19 patients operated on after 2013 underwent pre-parathyroidectomy PVS, with various surgical extents, and no permanent hypoparathyroidism (p = 0.033) or post-LPX recurrence was observed. Although TPX with auto-transplantation is the standard surgery for MEN1-related PHPT, surgical extent individualisation is necessary, given the postoperative hypoparathyroidism rate of TPX and feasibility of PVS.

Parathyroidectomy in First Trimester of Pregnancy

Primary hyperparathyroidism is not commonly diagnosed during pregnancy. For pregnant women with mild, asymptomatic disease, surgery can be avoided unless the degree of hypercalcemia becomes more severe or they develop complications. However, there are no evidence-based guidelines to assist clinicians regarding the management of primary hyperparathyroidism during pregnancy. When surgery is deemed necessary during pregnancy, the second trimester is generally considered to be the optimal time. We report the case of a 31-year-old female G1P0 who presented at 6 weeks gestation with symptoms of nausea, vomiting, polyuria, and corrected calcium of 14.8 mg/dL. Due to the extreme degree of hypercalcemia and refractory to medical treatment, it was decided that surgery could not be delayed until the second trimester. At 7w3d gestational age the patient had resection of a 37 gram, 5 × 4 × 3 cm right inferior parathyroid adenoma.

Author's reply to letter at the editor: primary hyperparathyroid surgery under local anaesthesia: benefits of hypnosis

The hypnosis gives more comfort to the patient and can be used in patients at risk of a general anaesthesia.