Minimally invasive open parathyroidectomy in an endemic goiter area: a prospective study

Primary Hyperparathyroidism and Intraoperative Parathyroid Hormone Monitoring: Application of a Modified Interpretation in Patients With "Parathyroid Hormone Spikes"

INTRODUCTION

Intraoperative parathyroid hormone (PTH) spikes occur in up to 30% of patients during surgery for primary hyperparathyroidism. This can lead to a prolonged PTH decline and cause difficulties in using current interpretation criteria of intraoperative PTH monitoring. The aim of this study aim was to evaluate an alternative interpretation model in patients with PTH spikes during exploration.

METHODS

1035 consecutive patients underwent surgery for primary hyperparathyroidism in a single center. A subgroup of patients with intraoperative PTH spikes of >50 pg/mL were selected (n = 277; 27.0%). The prediction of cure applying the Miami and Vienna criteria was compared with a decay of ≥50% 10 min after excision of the enlarged parathyroid gland using the "visualization value" (VV; =PTH level immediately after visualization of the gland) as basal value. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated.

RESULTS

Using the VV, sensitivity was 99.2% (Vienna 71.0%; Miami 97.7%), specificity was 18.2 (Vienna 63.6%; Miami 36.4%), and accuracy was 92.8 (Vienna 70.4%; Miami 92.8%). Of 255 single-gland disease patients, 72 were identified correctly as cured by applying the VV (P < 0.001), yet 10 of 22 patients with multiple-gland disease were missed compared with the Vienna Criterion (P = 0.002). The comparison with the Miami Criterion showed that six more patients were correctly identified as cured (P = 0.219), whereas four patients with multiple-gland disease were missed (P = 0.125).

CONCLUSIONS

Using the VV as a baseline in patients with intraoperative PTH spikes may prove to be an alternative and therefore can be recommended. However, if the VV is higher than the preexcision value, it should not be applied.

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.

Accessing the influence of 99mTc-Sesta-MIBI-positive thyroid nodules on preoperative localisation studies in patients with primary hyperparathyroidism

Purpose

Curative treatment for primary hyperparathyroidism (PHPT) is parathyroidectomy (PTX) with removal of the hyperfunctioning gland(s). In an endemic goitre region, 35–78% of PHPT patients show concomitant thyroid disease. This study aimed to evaluate if ^99mTc-sestamibi (MIBI)-positive thyroid nodules decrease sensitivity in regard to localising the hyperfunctioning parathyroid gland(s) in PHPT patients.

Methods

Within 5 years, 497 consecutive patients with biochemically proven PHPT were included in this study. The data was analysed retrospectively.

Results

In total, 198 patients underwent PTX with thyroid surgery and 299 patients underwent sole PTX. Sensitivity of MIBI scan for PTX with and without thyroid surgery was 72.1% and 73.6%, respectively. A statistically significant difference in sensitivity of ultrasound for PTX with and without thyroid surgery (57.0% and 70.9%, respectively) was observed (p = 0.029). Thyroid nodule histology did not have a significant effect on the MIBI scan. Unilateral neck exploration (UNE) was performed in 110 patients and bilateral neck exploration (BNE) in 177 patients. The probability of surgical conversion from UNE to BNE due to incorrect localisation was 1.733 times higher in patients with thyroid nodules.

Conclusions

Concomitant benign thyroid nodules did not influence MIBI sensitivity. No correlation between thyroid carcinoma and MIBI uptake was determined. However, MIBI detection of thyroid malignancy is important in patients initially being considered for minimal invasive parathyroidectomy. Sensitivity and positive predictive value of ultrasound were significantly lower in patients with thyroid nodules. The probability of conversion from UNE to BNE due to incorrect localisation was 1.733 times higher in patients with thyroid nodules.

Direct Comparison of Preoperative Imaging Modalities for Localization of Primary Hyperparathyroidism: A Systematic Review and Network Meta-analysis

Importance

Accurate preoperative localization of primary hyperparathyroidism (pHPT) is an important and challenging issue for a successful parathyroidectomy. Although new imaging modalities have been introduced during the past decade, direct comparative studies on advanced imaging techniques are limited.

Objective

To compare the performance of different preoperative imaging modalities for the localization of pHPT by performing a network meta-analysis (NMA).

Data Sources

PubMed, Embase, and the Cochrane Library were searched from the earliest available indexing date through September 28, 2020.

Study Selection

The inclusion criteria were diagnostic tests with sensitivities of 2 or more different preoperative imaging modalities for the same indivduals.

Data Extraction and Synthesis

Two researchers independently reviewed the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension statement of health care intervention guidelines for network meta-analyses.

Main Outcomes and Measures

After classifying various imaging modalities into 8 representative imaging categories, the pooled estimation between the odds ratio and 95% credible intervals (CrIs) was calculated in the sensitivity for localization of pHPT. The surface under the cumulative ranking curve (SUCRA) values were obtained to calculate the probability of each imaging modality being the most effective diagnostic method.

Results

A total of 8495 patients from 119 direct comparative studies using 2 or more imaging modalities for localization of pHPT were included. The sensitivity of choline positron emission tomography and computed tomography (PET-CT) was significantly higher than that of technetium 99m sestamibi single-photon emission computed tomography (MIBI SPECT) in both patient-based and lesion-based analyses (patient-based analysis: odds ratio, 5.22; 95% CrI, 2.36-11.80; lesion-based analysis: odds ratio, 17.70; 95% CrI, 5.79-60.10). Among 8 representative imaging modality categories, choline PET-CT showed the highest SUCRA value in both patient-based and lesion-based analyses. In patient-based analysis after 2010, choline PET-CT showed the highest SUCRA value, followed by the CT category, although MIBI SPECT had the highest SUCRA value in analysis before 2009.

Conclusions and Relevance

The results from this network meta-analysis suggest that choline PET-CT showed the best performance in both patient-based and lesion-based analyses and that choline PET-CT would be the best preoperative imaging modality for localization of pHPT.

Outcomes of Parathyroidectomy in Patients with Primary Hyperparathyroidism: A Systematic Review and Meta-analysis

BACKGROUND

Parathyroidectomy is a definitive treatment for primary hyperparathyroidism. Patients contemplating this intervention will benefit from knowledge regarding the expected outcomes and potential risks of the currently available surgical options.

PURPOSE

To appraise and summarize the available evidence regarding benefits and harms of minimally invasive parathyroidectomy (MIP) and bilateral neck exploration (BNE).

DATA SOURCES

A comprehensive search of multiple databases (MEDLINE, EMBASE, and Scopus) from each database's inception to September 2014 was performed.

STUDY SELECTION

Eligible studies evaluated patients with primary hyperparathyroidism undergoing MIP or BNE.

DATA EXTRACTION

Reviewers working independently and in duplicate extracted data and assessed the risk of bias.

DATA SYNTHESIS

We identified 82 observational studies and 6 randomized trials at moderate risk of bias. Most of them reported outcomes after MIP (n = 71). Using random-effects models to pool results across studies, the cure rate was 98 % (95 % CI 97-98 %, I (2) = 10 %) with BNE and 97 % (95 % CI 96-98 %, I (2) = 86 %) with MIP. Hypocalcemia occurred in 14 % (95 % CI 10-17 % I (2) = 93 %) of the BNE cases and in 2.3 % (95 % CI 1.6-3.1 %, I (2) = 87 %) with MIP (P < 0.001). There was a statistically significant lower risk of laryngeal nerve injury with MIP (0.3 %) than with BNE (0.9 %), but similar risk of infection (0.5 vs. 0.5 %) and mortality (0.1 vs. 0.5 %).

LIMITATIONS

The available evidence, mostly observational, is at moderate risk of bias, and limited by indirect comparisons and inconsistency for some outcomes (cure rate, hypocalcemia).

CONCLUSION

MIP and BNE are both effective surgical techniques for the treatment of primary hyperparathyroidism. The safety profile of MIP appears superior to BNE (lower rate of hypocalcemia and recurrent laryngeal nerve injury).

Rapid intraoperative determination of intact parathyroid hormone during surgery for primary hyperparathyroidism. Experience at our center

INTRODUCTION

Primary hyperparathyroidism (PHPT) is due to a single adenoma in 85%-95% of cases, and is often cured after adenoma removal. Intraoperative rapid determination of intact parathyroid hormone (PTHio) may be a tool for monitoring the effectiveness of PHPT surgery. The main objective of our study was to evaluate PTHio determination and to establish whether its successful implementation contributed to achieve minimally invasive surgery (MIS) and major ambulatory surgery (MAS) in the treatment of PHPT.

MATERIAL AND METHODS

Retrospective study of a consecutive series of patients diagnosed and operated on for PHPT at the University General Hospital of Ciudad Real between January 2005 and January 2012.

RESULTS

In the study period, 91 patients underwent surgery. 39 (42.9%) under general anesthesia, while 52 (57.1%) were candidates for regional anesthesia by cervical block. Seventy-six of all patients (83.5%) were amenable to MIS using a unilateral approach. Classical cervicotomy was performed in all other patients. PTHio determination was done in 75 patients, showing cure in the same surgery in 68 of them. MAS was performed in 70.3% (64) of patients.

CONCLUSIONS

Determination of PTHio may allow for changing the surgical approach to PHPT at our department, allowing for performance of MIS on an outpatient basis in a significant proportion of patients with some cosmetic improvement, probably less pain, shorter hospital stay, and less potential complications than bilateral cervical exploration.

Use of minimally invasive parathyroidectomy techniques in sporadic primary hyperparathyroidism: systematic review

The past two decades have seen rapidly changing attitudes towards the surgical management of primary hyperparathyroidism. Advances in localisation techniques and confidence with endoscopy have led to the development of numerous minimally invasive parathyroidectomy approaches, including open minimal incision and endoscopic and video-assisted parathyroidectomy. This paper systematically reviews the evidence for these methods to determine: (1) whether these new, minimally invasive techniques are comparable to conventional bilateral neck exploration methods in terms of success and complication rate; and (2) if they are comparable, which technique is likely to be best for cosmesis, patient safety and patient satisfaction. A search of the Medline, Cochrane Reviews and Scopus databases was conducted, using a defined list of search parameters. Abstracts were compared against inclusion and exclusion criteria, before the full text was sought and analysed for data. The evidence from each study was then assessed, based on study quality, and a recommendation made based on the level of evidence available. There is level 1b evidence that minimally invasive surgery is comparable to bilateral neck exploration in terms of efficacy and complication rates. This paper recommends that the treatment of choice for solitary adenoma (in most healthcare centres) should be open minimal incision parathyroidectomy, due to advantages in operative duration, learning curve and cost-effectiveness.

Is minimally invasive parathyroidectomy without QPTH monitoring justified?

BACKGROUND

It is matter of discussion if quick parathyroid hormone (QPTH) monitoring is helpful in patients with primary hyperparathyroidism (PHPT) and "localized single-gland disease" (SGD; concordant sestamibi and ultrasound results) to further increase the rate of success (permanent normocalcemia) of performing selective parathyroidectomy by minimally invasive parathyroid exploration (MIP). The aim of this study was to evaluate if a randomized controlled trial was justified in order to clarify this discussion.

MATERIALS AND METHODS

The prospective database of patients with sporadic PHPT, SGD, MIP, and QPTH monitoring (1999-2005) was evaluated regarding the "conversion rate" to bilateral exploration and permanent normocalcemia ("QPTH" group). Retrospectively, the patients were analyzed a second time "without" applying QPTH monitoring ("non-QPTH" group). Statistical differences between both groups were calculated (McNemar's test).

RESULTS

By definition, 338 patients with "localized SGD" underwent MIP. MIP was finished in 308 (91.1%) patients. Five of 308 patients (1.6%) showed persisting (n = 1) or recurrent disease (n = 4). In 30 of 338 patients (8.9%), a conversion to bilateral exploration was necessary (false preoperative localization 15 patients--one patient not cured; multiple-gland disease correctly indicated by QPTH monitoring 15 patients--one patient not cured). Analyzing the "non-QPTH" group, 14 additional patients showed persisting disease. Thus, without using QPTH monitoring, the rate of persisting PHPT would increase from 0.9% (three patients) to 5.0% (17 patients; p = 0.0005).

CONCLUSION

Intraoperative QPTH assay seems necessary even in patients with "localized SGD" by two techniques in an endemic goiter region. Abandoning QPTH monitoring would more than double the rate of persisting disease. A randomized trial seems not to be justified.

A "defined baseline" in PTH monitoring increases surgical success in patients with multiple gland disease

BACKGROUND

Parathyroid hormone (PTH) monitoring with a quick intact PTH (QIPTH) assay is used in minimally invasive exploration for primary hyperparathyroidism (PHPT) in order not to miss multiple gland disease (MGD). Controversy exists on which criterion is most reliable to predict cure.

METHODS

QIPTH values of 310 consecutive patients (single gland disease [SGD]: n = 289; MGD: n = 21) with sporadic PHPT were analyzed using 3 different criteria: "Vienna Criterion": >/=50% decay from a defined "baseline" level (right after induction of anesthesia before skin incision) 10 min after excision. "Miami Criterion": >/=50% decay from highest (preincision or preexcision) value 10 min after excision; "Halle Criterion": decay of the PTH- level to less than or equal to 35 pg/mL within 15 min after excision.

RESULTS

The "Vienna" and "Halle Criteria" correctly detected MGD in 19 (91%) and the "Miami Criterion" in 12 (57%) of 21 patients. Incorrect prediction of incomplete excision occurred in 22 patients (8%) with SGD, using the "Vienna Criterion" ("Miami Criterion": 2%, "Halle Criterion": 29%). All of these were recognized intraoperatively from unintended intraoperative manipulation (n = 18), technical failure (n = 2), or borderline increased PTH values (n = 2), and they did not lead to bilateral exploration. Analyzing patients with SGD and MGD, accuracy and specificity were 92% and 89% for the "Vienna Criterion," 93% and 54% applying the "Miami Criterion," and 72% and 89% using the "Halle Criterion."

CONCLUSION

Strict definition of a PTH "baseline level" ("Vienna Criterion") improves intraoperative diagnosis of MGD, thus reducing reoperations and increasing long-term cure.

[Influence of quick intraoperative measurements of intact parathyroid hormone in the surgical management of primary hyperparathyroidism]

OBJECTIVE

To evaluate whether a quick parathyroid hormone assay that measures intact parathyroid hormone (iPTH) level intraoperatively has modified the surgical strategy for primary hyperparathyroidism in the Meixoeiro Hospital in Vigo (Pontevedra, Spain).

DESIGN

An observational, analytic, historic cohort study was performed. Two study groups were established. In group 1 (n = 28) iPTH levels were not measured intraoperatively. In group 2 (n = 39) iPTH was measured intraoperatively. iPTH was monitored using blood samples from cannulated peripheral veins. A positive test was defined as a decrease in iPTH level of >or= 50% of the baseline preincision level at 10 minutes postexcision, even when the baseline value was outside the normal range. The dependent variables evaluated were operating time, the number of parathyroid glands visualized, the number of parathyroid glands biopsied, length of postoperative hospital stay, unilateral exploration, and the percentages of cure, persistence, and recurrence in each group.

RESULTS

Group 2 showed a statistically significant decrease in operating time (144.7 +/- 62.1 versus 178.8 +/- 57.5 minutes; p = 0.025), the number of parathyroid glands visualized (1.9 +/- 0.9 versus 2.8 +/- 1.3; p = 0.002), the number of parathyroid glands biopsied (1.5 +/- 0.9 versus 2.2 +/- 1.4; p = 0.025), and the need for bilateral exploration (30.77% versus 85.72%) in comparison with group 1. No significant differences were observed in length of postoperative hospital stay or in the percentages of cure (94.8% versus 92.85%), persistence (5.12% versus 7.14%), and recurrence (2.56% versus 3.57%).

CONCLUSIONS

In our hospital, intraoperative measurement of iPTH improved the surgical strategy of primary hyperparathyroidism and has therefore been included in our routine treatment protocol.

PTH spikes during parathyroid exploration--a possible pitfall during PTH monitoring?

BACKGROUND AND AIMS

Parathyroid hormone (PTH) spikes caused by unintentional manipulation of the hypersecreting glands may lead to interpretation problems in intraoperative PTH monitoring. Their frequency and surgical consequences were evaluated.

MATERIALS AND METHODS

Intraoperative PTH values of 401 patients with primary hyperparathyroidism and single gland disease were analysed. Patients were divided into four groups: extensive increase (>150 pg/ml), moderate PTH increase (<150 pg/ml), no increase (+/-50 pg/ml) and decrease before excision as referred to the baseline level before skin incision. PTH was measured before and up to 25 min after removal of the enlarged gland.

RESULTS

Twenty-two (5.5%) patients had an extensive and 36 (9%) a moderate intraoperative PTH increase. The PTH decline was prolonged to 15 min in 7 (31.8%) and to 25 min in 12 (54.5%) patients after extensive manipulation and in 9 patients (25%) each after moderate manipulation, respectively. No increase occurred in 162 (40.4%) and a decrease in 181 (45.1%) patients. The surgical approach (bilateral exploration vs open, minimally invasive parathyroidectomy) did not show a difference in the rate of PTH spikes.

CONCLUSION

PTH spikes often cause a prolonged PTH decline but, when recognized, do not lead to a change in the surgical strategy.

Parathyroid Hormone Monitoring during Total Parathyroidectomy for Renal Hyperparathyroidism: Pilot Study of the Impact of Renal Function and Assay Specificity

Background: Commonly used assays for intact parathyroid hormone (iPTH) detect not only the biologically active 84–amino acid hormone [PTH(1–84)], but cross-react with an N-terminal–truncated fragment. Because iPTH assays often fail to predict success of parathyroidectomy in patients with renal hyperparathyroidism (rHPT), we compared results of a 3rd-generation PTH(1–84) assay (Bio-iPTH; Nichols Institute Diagnostics) with two 2nd-generation iPTH assays (from Nichols and Roche Diagnostics) by evaluating the PTH clearance kinetics during surgical treatment.

Methods: We collected blood samples in short time intervals from 35 consecutive surgical patients with rHPT. Three patients had to be excluded from further calculations; the remainder were grouped according to kidney function and postoperative outcome. All samples were analyzed with the 3 automated PTH assays, which have different specificities.

Results: Twenty minutes after removal of the last gland, the PTH(1–84) values decreased to within the reference intervals in all patients with total and subtotal resection; however, iPTH concentrations normalized in only one half of these patients. In patients with poor renal function, the half-life of PTH(1–84) was shorter than the half-lives obtained with the iPTH assays.

Conclusions: The accuracy of PTH monitoring during surgery for rHPT depends on renal function and assay specificity. All assays tested showed similar effectiveness in detecting missed glands, but the assay for PTH(1–84) gave more reliable results than the iPTH assays, which overestimated the concentration of PTH and hampered the intrasurgical diagnosis of resection sufficiency.

[Open minimally invasive parathyroid and thyroid surgery]

Open minimally invasive parathyroidectomy or thyroidectomy (small-incision technique) are frequently performed. Benefits and disadvantages of this approach are discussed in this review. Preoperative patients selection is mandatory and is also discussed.

A systematic review of the diagnosis and treatment of primary hyperparathyroidism from 1995 to 2003

OBJECTIVE

To systematically review the current preoperative diagnostic modalities, surgical treatments, and glandular pathologies associated with primary hyperparathyroidism.

STUDY DESIGN

A systematic literature review.

RESULTS

Of the 20,225 cases of primary hyperparathyroidism reported, solitary adenomas (SA), multiple gland hyperplasia disease (MGHD), double adenomas (DA), and parathyroid carcinomas (CAR) occurred in 88.90%, 5.74%, 4.14%, and 0.74% of cases respectively. Tc 99m -sestamibi and ultrasound were 88.44% and 78.55% sensitive, respectively, for SA, 44.46% and 34.86% for MGHD, and 29.95% and 16.20% for DA, respectively. Postoperative normocalcemia was achieved in 96.66%, 95.25%, and 97.69% of patients offered minimally invasive radio-guided parathyroidectomy (MIRP), unilateral, and bilateral neck exploration (BNE). Intraoperative PTH assays (IOPTH) were helpful in approximately 60% of bilateral neck exploration conversion (BNEC) surgeries.

CONCLUSION

The overall prevalence of multiple gland disease (MGD and DA) was lower than often suggested by conventional wisdom. Furthermore, preoperative imaging was less accurate than it is often perceived for accurately imaging MGD. MIRP and UNE were more successful in achieving normocalcemia than is typically quoted. IOPTH was a helpful but not "fool-proof" adjunct in parathyroid exploration surgery.

SIGNIFICANCE

These results support a greater role for the treatment of primary hyperparathyroidism using less invasive approaches. EMB rating: B-3.

Predictive value of intact parathyroid hormone measurement during surgery for renal hyperparathyroidism

BACKGROUND AND AIMS

In contrast to that in patients with primary hyperparathyroidism, the value of intraoperative intact parathyroid hormone (iPTH) measurement is still unclear in patients with renal hyperparathyroidism and was, therefore, evaluated in a large cohort of patients.

PATIENTS

Intraoperative iPTH measurement was performed in 153 patients with renal hyperparathyroidism (129 with terminal renal failure and 24 with functioning kidney graft). Subtotal and total parathyroidectomy were performed in 123 and 13 patients, respectively, during initial surgery. In patients with recurrent disease (17), the respective hyperfunctioning tissue was removed. Intraoperative blood samples were obtained by puncture of the internal jugular vein before preparation of the parathyroids (PTH0) and 15 min after parathyroidectomy (PTH15). iPTH was measured with the Elecsys 2010 system. Postoperative iPTH levels (PTH(post)) were determined at postoperative days 1 to 3 and at week 2. Patients were arbitrarily divided in four groups according to the postoperative iPTH values: 0-25 pg/ml (group 1), 26-65 pg/ml (group 2), 66-150 pg/ml (group 3) and more than 150 pg/ml (group 4).

RESULTS

The mean PTH0 value was 869+/-57 pg/ml, which decreased to 167+/-15 pg/ml at PTH15. The mean relative PTH15 value was 21.6+/-1.7%. Postoperatively, iPTH decreased to 42+/-9 pg/ml. The postoperative iPTH value of the 129 patients with terminal renal failure was 25 pg/ml or less in 99 patients, 26-65 pg/ml in 11 patients, 66-150 pg/ml in eight patients and higher than 150 pg/ml in 11 patients. Two successive criteria of iPTH decrease were used: first, a PTH15 of < or =150 pg/ml or, second, a relative PTH15 of < or =30% less was used. Fifteen patients did not fulfil both criteria. In 13 of them (86.7%) iPTH(post) was higher than 65 pg (true failure to decline). Of 114 patients who fulfilled the criteria, 108 (94.7%) had normal postoperative iPTH values (true decline). Absolute PTH15 values of less than 150 pg/ml predicted normal postoperative iPTH levels in 77 of 78 patients.

CONCLUSION

A PTH15 value of 150 pg/ml or less predicts operative success in patients with renal failure in 98.7% of cases, independently of the relative decay. In contrast, if the relative PTH15 is higher than 30%, high postoperative PTH values are predicted with a probability of 86.7%. Although there remain some borderline cases, intraoperative iPTH measurement is accurate and also can be useful in patients with renal hyperparathyroidism.

Effects of parathyroidectomy on lead mobilization from bone in patients with primary hyperparathyroidism

Since lead (Pb) accrued from environmental exposure accumulates in bone with a half life time between 6 and 10 years, a release of bone Pb into the circulation and/or urine (PbU) should be expected in diseases with increased bone metabolism such as hyperparathyroidism. We studied 60 patients with primary hyperparathyroidism (pHPT, 50 women, 10 men, aged 61.4 +/- 10.6 and 64.1 +/- 9.9 years, respectively) (a) before, (b) 1-6 months, and (c) 6-12 months after parathyroidectomy. Besides lead in blood (PbB) and lead in 24-h urine samples (PbU), parathyroid hormone (PTH), serum Ca2+, osteocalcin (OC), phosphate (PO4), and serum pyridinoline cross-linked telopeptide (cTP) were determined. Control data were determined in 20 healthy age-matched subjects. As expected, Ca2+ decreased after parathyroidectomy. Mean PbB in patients with pHPT was in the same range as in controls. A decrease of PbB after parathyroidectomy was found in the interval beyond 6 months. In contrast, mean PbU initially increased after surgery (3.05 +/- 1.94 vs. 4.25 +/- 2.65 microg/l, P = 0.004) and was not different beyond 6 months in comparison with preoperative values at (c). Investigating only patients with PTH < 150 ng/l, no significant PbB or PbU alterations were detected before and after parathyroidectomy. In patients with PTH > 150 ng/l, the decrease of PbB at (c) was more pronounced as was the increase of PbU at (b). In these patients, PbB and OC as well as PbB and cTP were correlated preoperatively. In conclusion, our data show that in environmentally lead-exposed (by food or by pollution) hyperparathyroid individuals, there is no hazardous PbB release from bone. The preoperative correlation between PbB and OC in pHPT patients with PTH > 150 ng/l provides evidence that in fact there is a Pb release from bone into the blood-pool by bone remodeling. The increase of PbU after parathyroidectomy is suspected to be caused by PTH-dependent Pb accumulation in the kidney, which seems to be restored with decreasing PTH. Moreover, our data confirm prior findings that bone remodeling seems to be normalized 6 months after parathyroidectomy.

Prevention and management of complications in parathyroid surgery

The most common complication of parathyroid surgery is operative failure. Recurrent laryngeal nerve paralysis, permanent hypoparathyroidism,hematoma, and error in diagnosis can also complicate initial parathyroid exploration. This article discusses specific ways to try to prevent these and other problems and gives detailed strategies to evaluate and manage affected patients.

Computed axial tomography–MIBI image fusion for preoperative localization in primary hyperparathyroidism

BACKGROUND

An imaging-guided unilateral surgical approach in patients with primary hyperparathyroidism (HPTH) requires reliable preoperative localization procedures. Using present imaging techniques, 60% to 80% of patients with primary HPTH can be treated successfully with limited surgery. Thus, further improvement of diagnostic accuracy is required. Computed axial tomography (CAT)-MIBI image fusion was introduced as a new technique for localizing enlarged parathyroid glands. We describe the new method and present its first results.

METHODS

Six consecutive patients with primary HPTH underwent CAT-MIBI image fusion for preoperative parathyroid localization. CAT and technetium-99m-sestamibi scan were performed separately. The patient's head and neck were fixed with the noninvasive Vogele-Bale-Hohner Head Holder (VBH HeadFIX; Medical Intelligence, Schwabmünchen, Germany) and the BodyFIX (Medical Intelligence) vacuum cushion. Radiographic and scintigraphic markers were mounted at the head holder and the patient. CAT and MIBI images were fused by overlaying radiographic markers using a commercial software and workstation.

RESULTS

In 5 patients, localization and dimension of the solitary adenomas were exactly predicted. In 1 patient with multiglandular disease (3 enlarged glands), CAT-MIBI image fusion was not able to predict multiple gland involvement. However, in a retrospective analysis of the localization study, the other two enlarged parathyroid glands could be correctly identified regarding their site and size.

CONCLUSIONS

First results of CAT-MIBI image fusion are promising. The new technique provides a higher image resolution and better delimitation of enlarged parathyroid glands and adjacent anatomic structures than conventional scintigraphic methods.

Prospective evaluation of ultrasonography plus MIBI scintigraphy in selecting patients with primary hyperparathyroidism for unilateral neck exploration under local anaesthesia

BACKGROUND

Unilateral neck exploration (UNE) is currently replacing conventional bilateral neck exploration with cervicotomy for the surgical treatment of primary hyperparathyroidism (PHPT). However, many concerns still exist about the indications and the effectiveness of this minimally invasive approach.

METHODS

Prospective evaluation of operative results in consecutive patients having indications for UNE on the basis of strict selection criteria consisting of ultrasound-MIBI agreement in adenoma localization, absence of thyroid disease, and psychological suitability for undergoing a procedure under local anesthesia. No intraoperative confirmation study was adopted.

RESULTS

Among 149 consecutive PHPT patients, 45 (30.2%) had indications for UNE. No operative morbidity or mortality was observed. Mean operative time for the UNE procedure was 42 minutes (range 25 to 57). Conversion to general anesthesia was chosen for 5 patients (11.1%), whereas conversion to bilateral neck exploration was chosen for 3 patients (6.6%). For the UNE procedure, the success rate was as high as 91.7%. When the only factor indicated UNE, ultrasound-MIBI localization agreement had low sensibility (44.1%) and specificity (55.6%) but a high positive predictive value (91.1%).

CONCLUSIONS

We concluded that UNE performed under local anesthesia, without intraoperative confirmation studies, could be considered a safe and effective approach to treating patients with PHPT, but we regret the low rate of patients selected for this procedure because of the low sensitivity of the imaging-inclusion criterion.

CT-MIBI image fusion: A new preoperative localization technique for primary, recurrent, and persistent hyperparathyroidism

BACKGROUND

Successful minimally invasive or imaging-guided operations in patients with primary, recurrent, and persistent hyperparathyroidism are based on the reliability of preoperative parathyroid localization studies. The CT-MIBI image fusion promises a higher diagnostic accuracy than current imaging procedures. The aim of our study was to assess its reliability in correctly detecting enlarged parathyroid glands.

METHODS

In a prospective study 24 consecutive patients underwent CT-MIBI image fusion as preoperative parathyroid localization procedure. The results of technetium 99m sestamibi single photon emission computed tomography (MIBI-SPECT) alone, today the standard method in parathyroid imaging, and CT-MIBI image fusion were analyzed by a blinded reviewer, and the imaging results were compared with the intraoperative findings.

RESULTS

For CT-MIBI image fusion a sensitivity of 93% and a specificity of 100% in correctly detecting the position of enlarged parathyroid glands was calculated and compared with a sensitivity of MIBI-SPECT of 31% and a specificity of 87% (P<.001). This new imaging technique enabled us to successfully treat 22 of our patients (92%) with imaging-guided surgery. Twenty (83%) underwent unilateral or minimally invasive operations.

CONCLUSIONS

CT-MIBI image fusion appears to be superior to MIBI-SPECT in preoperative parathyroid imaging. CT-MIBI image fusion can be performed on existing CT- and MIBI-SPECT units. We recommend this method for preoperative localization in patients with primary, recurrent and persistent hyperparathyroidism.

Impact of intraoperative parathyroid hormone monitoring on the prediction of multiglandular parathyroid disease

Optimal interpretation of the results of intraoperative parathyroid hormone (IOPTH) monitoring during neck exploration for primary hyperparathyroidism (pHPT) is still controversial. The reliability of the "50% rule" in multiglandular disease (MGD) is often disputed, mostly because of competing pathophysiologic paradigms. The aim of this study was to ascertain and corroborate the ability of IOPTH monitoring to detect MGD in a practice, combining conventional and alternative parathyroidectomy techniques. This is a retrospective single institution analysis of 69 consecutive patients undergoing cervical exploration for pHPT by various approaches. The IOPTH measurements were performed after induction of anesthesia but prior to skin incision and 10 minutes after excision of the first visualized enlarged parathyroid gland. In this series, 55 patients (80%) had single adenomas, and 14 patients (20%) had MGD. In 8 of the 14 patients with MGD, IOPTH levels were obtained sequentially after removal of every enlarged gland. Of these 8 patients, 6 (75%) had a false-positive decrease (decrease below 50% of baseline value in presence of another enlarged gland) failing to predict the presence of a second enlarged gland. In 2 cases IOPTH monitoring provided a true-negative result, correctly predicting MGD. If MGD is defined by gross morphologic criteria, IOPTH monitoring fails to predict the presence of MGD reliably. However, if MGD is defined by functional criteria, the course of these patients does not seem significantly affected. The importance of these findings must be further investigated, especially with regard to the outcome of minimally invasive parathyroid procedures.

Impact of intraoperative parathyroid hormone monitoring on the prediction of multiglandular parathyroid disease

Optimal interpretation of the results of intraoperative parathyroid hormone (IOPTH) monitoring during neck exploration for primary hyperparathyroidism (pHPT) is still controversial. The reliability of the "50% rule" in multiglandular disease (MGD) is often disputed, mostly because of competing pathophysiologic paradigms. The aim of this study was to ascertain and corroborate the ability of IOPTH monitoring to detect MGD in a practice, combining conventional and alternative parathyroidectomy techniques. This is a retrospective single institution analysis of 69 consecutive patients undergoing cervical exploration for pHPT by various approaches. The IOPTH measurements were performed after induction of anesthesia but prior to skin incision and 10 minutes after excision of the first visualized enlarged parathyroid gland. In this series, 55 patients (80%) had single adenomas, and 14 patients (20%) had MGD. In 8 of the 14 patients with MGD, IOPTH levels were obtained sequentially after removal of every enlarged gland. Of these 8 patients, 6 (75%) had a false-positive decrease (decrease below 50% of baseline value in presence of another enlarged gland) failing to predict the presence of a second enlarged gland. In 2 cases IOPTH monitoring provided a true-negative result, correctly predicting MGD. If MGD is defined by gross morphologic criteria, IOPTH monitoring fails to predict the presence of MGD reliably. However, if MGD is defined by functional criteria, the course of these patients does not seem significantly affected. The importance of these findings must be further investigated, especially with regard to the outcome of minimally invasive parathyroid procedures.

Intraoperative testing for parathyroid hormone: a comprehensive review of the use of the assay and the relevant literature

OBJECTIVE

The rapid intraoperative parathyroid hormone assay is transforming the parathyroidectomy procedure. We present a review of the literature on the use of the assay as an adjunct to surgery. To our knowledge, this is the first review of the literature to encompass and compare all known primary studies of this assay in parathyroidectomy patients.

DATA SOURCES

Articles were collected by searching MEDLINE databases using relevant terminology. The references of these articles were reviewed for additional studies. Supplementary articles pertinent to the parathyroidectomy procedure, preoperative parathyroid localization studies, and intraoperative parathyroid hormone assay development also were examined.

STUDY SELECTION AND DATA EXTRACTION

One hundred sixty-five references were analyzed and categorized separately into groups.

DATA SYNTHESIS

The primary studies of intraoperative data on patients undergoing parathyroidectomy were compared when possible. Studies were analyzed by type of assay used, where performed, turnaround time, and efficiency of use. Reviews of the types of parathyroid surgery and preoperative localization were included for educational purposes.Conclusions.-The intraoperative parathyroid hormone assay is a useful adjunct to preoperative imaging and parathyroid surgery because of its unique ability to detect an occult residuum of hyperfunctioning parathyroid tissue. Use of this assay will obviate the need for frozen section in most routine cases. The test facilitates minimally invasive parathyroidectomy for single parathyroid adenomas, which, in turn, improves cost-effectiveness and cosmetic outcome. Its use in patients with known preoperative multiglandular disease is promising but requires further study.

Impact of localization studies on feasibility of minimally invasive parathyroidectomy in an endemic goiter region

BACKGROUND

A localized single-gland disease is the basis for minimally invasive parathyroidectomy (MIP) in primary hyperparathyroidism (PHPT). (99m)Tc sestamibi scanning (MIBI) and high-resolution Doppler ultrasonography (US) are well-established techniques used to localize enlarged parathyroid glands. Additionally, US enables physicians to diagnose subclinical thyroid abnormalities. The aim of this study was to optimize localization results, applying a combined interpretation of MIBI and US, and to analyze the influence of these results on the feasibility of MIP (endoscopic/video-assisted and open) in an endemic goiter region.

STUDY DESIGN

One hundred fifty consecutive patients with sporadic PHPT were prospectively subjected to MIBI and US to localize parathyroid lesions and to review the morphology of the thyroid gland. Bilateral cervical exploration was performed in all patients. The feasibility of MIP was calculated retrospectively on the basis of surgical findings and biochemical outcomes at least 12 months postoperatively (normocalcemia in 148 of 150 patients [99%]).

RESULTS

Forty-five percent of patients (67 of 148) would have been suitable for minimally invasive endoscopic or video-assisted parathyroid exploration. These procedures would have succeeded in 38% of patients (56 of 148). Sixty-four percent (94 of 148) would have been suitable for minimally invasive open parathyroidectomy, which would have succeeded in 55% (82 of 148 patients).

CONCLUSIONS

Not all patients are suitable for MIP. A combined interpretation of MIBI and US results is helpful in planning targeted exploration. In an endemic goiter region minimally invasive open parathyroidectomy is applicable in significantly more patients than is endoscopic and video-assisted MIP.

Surgical management of the parathyroids

The recent advance of intraoperative PTH monitoring combined with preoperative localization techniques allow for minimally invasive parathyroid surgery in 75% to 85% of cases. In cases where a single adenoma is identified, minimally invasive techniques should result in a need for repeat surgery in only 2% of cases. The cost of intraoperative PTH assays of localization and gamma probes limits their availability. Complications of parathyroidectomy are uncommon, but appropriate management is important, particularly for patients with hypocalcemia.

Improving the yield of preoperative parathyroid localization: technetium Tc 99m-sestamibi imaging after thyroid suppression

BACKGROUND

Preoperative localization is essential for successful directed, minimally invasive or reoperative parathyroidectomy. Standard technetium Tc 99m-sestamibi imaging is the most sensitive modality for localization. We reviewed our experience with (99m)Tc-sestamibi imaging and specifically investigated the effect of thyroid suppression on repeat imaging of patients who had initially nonlocalizing scans.

METHODS

. The records of patients who underwent (99m)Tc-sestamibi imaging during evaluation for primary hyperparathyroidism were reviewed. A subset of patients with initially nonlocalizing scans underwent thyroid suppression with either thyroxin or liothyronine and then had their scans repeated.

RESULTS

Ninety-nine patients with primary hyperparathyroidism underwent (99m)Tc-sestamibi imaging followed by parathyroidectomy (initial operation, 78; reoperation, 21). Successful parathyroid localization was obtained on standard imaging in 67 patients. Fourteen of 32 patients who had nonlocalizing (99m)Tc-sestamibi imaging studies underwent an additional scan after thyroid suppression. In 10 of 14 patients (71%), repeat (99m)Tc-sestamibi imaging after thyroid suppression successfully localized abnormal parathyroid tissue.

CONCLUSIONS

Thyroid suppression may improve the yield of (99m)Tc-sestamibi imaging in patients with hyperparathyroidism who have an initially nonlocalizing study. This diagnostic strategy may be helpful in patients motivated to undergo a directed, minimally invasive operation, as well as in the evaluation of patients for reoperative parathyroidectomy.

Kinetic Analyses of Parathyroid Hormone Clearance as Measured by Three Rapid Immunoassays during Parathyroidectomy

Background: Rapid intraoperative parathyroid hormone (PTH) measurements are an important prerequisite for minimally invasive parathyroidectomy, serving as a feasible marker for “cure” because of the short half-life of PTH. Because automated analysis may facilitate monitoring, two automated PTH assays were compared with an established manual method.

Methods: We collected 109 plasma samples during minimally invasive surgery on 20 patients with primary hyperparathyroidism and single-gland disease. PTH was analyzed manually with a test from Nichols and by two automated assays from Diagnostic Product Corporation (DPC) and Roche, respectively. PTH half-life and residual concentrations were calculated by two kinetic models.

Results: Despite good overall correlations between methods [DPC = 1.07(Nichols) − 12 ng/L; r = 0.95, Sy|x = 26 ng/L and Roche = 1.16(Nichols) − 2.82 ng/L; r = 0.98; Sy|x = 16 ng/L], marked interindividual differences were observed. The iterative kinetic model failed with a nonuniform PTH decrease, but the interpolative model produced valid results. The mean (SD) half-life of 3.7 ± 1.4 min with DPC differed significantly (P &lt;0.05) from the 4.3 ± 1.6 min with Roche (Nichols, 4.0 ± 1.6 min). DPC produced significantly lower mean residual PTH (15 ng/L) vs Roche (27 ng/L); Nichols results were between them (20 ng/L). However, these differences were clinically irrelevant.

Conclusions: Automated methods are as suitable as the manual test. The preoperative baseline PTH is necessary but is insufficient for kinetic calculations.