Minimally invasive procedure for resection of a parathyroid adenoma: the role of preoperative high-resolution ultrasonography

Selective venous sampling in primary hyperparathyroidism caused by ectopic parathyroid gland: a case report and literature review

BACKGROUND

As an invasive technique, selective venous sampling (SVS) is considered a useful method to identify a lesion's location to increase the success rate of secondary surgery in patients with primary hyperparathyroidism (pHPT) caused by ectopic parathyroid adenomas.

CASE PRESENTATION

We present a case of post-surgical persistent hypercalcemia and elevated parathyroid hormone (PTH) levels in a 44-year-old woman with previously undetected parathyroid adenoma. An SVS was then performed for further localization of the adenoma, as other non-invasive methods showed negative results. After SVS, an ectopic adenoma was suspected in the sheath of the left carotid artery, previously considered as a schwannoma, and was pathologically confirmed after the second operation. Postoperatively, the patient's symptoms disappeared and serum levels of PTH and calcium normalized.

CONCLUSIONS

SVS can provide precise diagnosis and accurate positioning before re-operation in patients with pHPT.

"Before skin incision" high-resolution ultrasound in primary hyperparathyroidism: a new imaging tool for surgeons?

PURPOSE

Various diagnostic methods have been utilized for localizing pathologic parathyroid glands to consequently provide the possibility of avoiding bilateral neck dissection in cases of primary hyperparathyroidism. Scintigraphy, combined with ultrasound, became established as the standard method of localization in the 2000s. The aim of this study was to evaluate the role of the "before skin incision" surgeon-performed ultrasound in determining the improvement in the diagnostic accuracy in a large case series.

METHOD

The method used in this research is a retrospective observational study (study period: between 1-2014 and 12-2020) comparing two patient groups before (control group: 31 patients) and after (study group: 70 patients) the introduction of the ultrasonography surgical protocol: combined preoperative and "before skin incision" surgeon-performed ultrasound.

RESULTS

The sensitivity of the combined preoperative "before skin incision" surgeon-performed ultrasound was 97%, and the positive predictive value was 93% in regard to detecting the number of diseased glands and the appropriate anatomic location (right versus left, upper versus lower). The sensitivity of the parathyroid scan (Tc-MIBI-scintigraphy) was 74%, and the positive predictive value was 92%. The duration of surgery was significantly shorter in the test group (84.7 vs. 66.4 min; Mann‒Whitney U: 0.006). No differences were detected between the two groups in regard to avoiding intraoperative or postoperative complications.

CONCLUSION

The combination of the preoperative "before skin incision" surgeon-performed ultrasound could improve the efficiency of the preoperative location and anatomic classification using the standard literature-suggested diagnostic methods.

Contemporary Management of Primary Hyperparathyroidism

Primary hyperparathyroidism can be asymptomatic or symptomatic, as well as classic, normocalcemic, or normohormonal. It is important to rule out other causes of hypercalcemia or hyperparathyroidism. Preoperative localization with imaging is necessary for a minimally invasive approach and can be helpful even if planning 4-gland exploration. There are a variety of intraoperative techniques that can assist with localization as well as confirming success. Standard of care remains surgical resection of affected glands. However, there are less invasive management strategies that can be considered for poor surgical candidates.

Correlation of Preoperative Imaging Findings and Parathyroidectomy Outcomes Support NICE 2019 Guidance

CONTEXT

Preoperative localization studies are standard practice in patients undergoing parathyroidectomy for primary hyperparathyroidism (pHPT). The most common modalities are neck ultrasound (US) and sestamibi scanning. However, the nature of pHPT is changing, with imaging increasingly yielding negative results. Numerous studies suggest unlocalized disease is associated with poor outcomes, calling into question whether such patients are best treated conservatively.

OBJECTIVE

This study aims to correlate parathyroidectomy outcomes with preoperative imaging in a single, high-volume institution.

METHODS

Data from a prospectively maintained departmental database of operations performed from 2017 to 2019 were analyzed. All patients undergoing first-time surgery for sporadic pHPT were included. Data collected included patient demographics, preoperative imaging, surgical strategy, and postoperative outcomes.

RESULTS

A total of 609 consecutive parathyroidectomies were included, with a median age of 59 years (range 20-87 years). The all-comer cure rate was 97.5%; this was 97.9% in dual localized patients (those with positive US and sestamibi), compared to 95.8% in the dual unlocalized group (those with negative US and sestamibi) (P = 0.33). Unilateral neck exploration was the chosen approach in 59.9% of patients with double-positive imaging and 5.7% of patients with double-negative imaging (otherwise, bilateral parathyroid visualization was performed). There was no significant difference in postoperative complications between patients undergoing unilateral or bilateral neck exploration.

CONCLUSIONS

Patients with negative preoperative imaging who undergo parathyroidectomy are cured in almost 96% of cases, compared to 98% when the disease is localized. This difference does not reach statistical or clinical significance. These findings therefore support current recommendations that all patients with pHPT who are likely to benefit from operative intervention should be considered for parathyroidectomy, irrespective of preoperative imaging findings.

The use of computed tomography as a first-line imaging modality in patients with primary hyperparathyroidism

BACKGROUND

The success of minimally invasive parathyroidectomy (MIP) relies on accurate localization of the abnormal parathyroid glands. Concordant findings on ultrasound (US) and ^99mTc-scintigraphy (sestamibi) are currently considered the 'gold standard'. Computed tomography (CT) has also recently been used in preoperative planning. We sought to assess the accuracy of CT for localization of abnormal parathyroid glands in such patients.

METHODS

An audit of 75 patients with primary hyperparathyroidism (PHPT) who underwent neck US and CT between 2017 and 2019 at our center as their first-line imaging.

RESULTS

All 75 patients underwent US and CT and 54 (72.0%) also had sestamibi. CT alone identified a potential target in all patients, of which the location was correct in 63 (84.0%). The overall combined sensitivity of US and CT was 88% (95% CI 78-94) and was higher than the combined sensitivity of US and sestamibi (65% [95% CI 53-76]; p < 0.001). Twenty-one patients (28.0%) had an ectopic gland, and the sensitivity of US and CT was 86% (95% CI 64-96) versus US and sestamibi (57% [95% CI 34-77]; p = 0.016). For adenomas < 1.0 g (n = 36; 48%), the accuracy of CT was 81% (95% CI 64-91) compared with 62% (95% CI 44-77) for US and sestamibi (p = 0.04). The correct preoperative diagnosis of multiglandular disease (n = 9; 12%) seemed to be the most difficult, with similar accuracy for US and sestamibi (40% [95% CI 14-73]) and US and CT (50% [95% CI 20-80]) (p > 0.99).

CONCLUSION

The combination of US and CT was able to correctly identify the location of the abnormal parathyroid in 88% of patients and, in comparison with US and sestamibi, had better diagnostic accuracy, especially for smaller and ectopic adenomas. This finding suggests that US and CT could be considered as a first-line imaging modality in patients with PHPT considered for MIP.

A cost-utility analysis of 18F-fluorocholine-positron emission tomography imaging for localizing primary hyperparathyroidism in the United States

BACKGROUND

Primary hyperparathyroidism historically necessitated bilateral neck exploration to remove abnormal parathyroid tissue. Improved localization allows for focused parathyroidectomy with lower complication risks. Recently, positron emission tomography using radiolabeled 18F-fluorocholine demonstrated high accuracy in detecting these lesions, but its cost-effectiveness has not been studied in the United States.

METHODS

A decision tree modeled patients who underwent parathyroidectomy for primary hyperparathyroidism using single preoperative localization modalities: (1) positron emission tomography using radiolabeled 18F-fluorocholine, (2) 4-dimensional computed tomography, (3) ultrasound, and (4) sestamibi single photon emission computed tomography (SPECT). All patients underwent either focused parathyroidectomy versus bilateral neck exploration, with associated cost ($) and clinical outcomes measured in quality-adjusted life-years gained. Model parameters were informed by literature review and Medicare costs. Incremental cost-utility ratios were calculated in US dollars/quality-adjusted life-years gained, with a willingness-to-pay threshold set at $100,000/quality-adjusted life-year. One-way, 2-way, and threshold sensitivity analyses were performed.

RESULTS

Positron emission tomography using radiolabeled 18F-fluorocholine gained the most quality-adjusted life-years (23.9) and was the costliest ($2,096), with a total treatment cost of $11,245 or $470/quality-adjusted life-year gained. Sestamibi single photon emission computed tomography and ultrasound were dominated strategies. Compared with 4-dimentional computed tomography, the incremental cost-utility ratio for positron emission tomography using radiolabeled 18F-fluorocholine was $91,066/quality-adjusted life-year gained in our base case analysis, which was below the willingness-to-pay threshold. In 1-way sensitivity analysis, the incremental cost-utility ratio was sensitive to test accuracy, positron emission tomography using radiolabeled 18F-fluorocholine price, postoperative complication probabilities, proportion of bilateral neck exploration patients needing overnight hospitalization, and life expectancy.

CONCLUSION

Our model elucidates scenarios in which positron emission tomography using radiolabeled 18F-fluorocholine can potentially be a cost-effective imaging option for primary hyperparathyroidism in the United States. Further investigation is needed to determine the maximal cost-effectiveness for positron emission tomography using radiolabeled 18F-fluorocholine in selected populations.

Radioguided occult lesion localization for minimally-invasive parathyroidectomy without quick PTH monitoring and frozen section: impact of the learning curve

Objectives

Minimally-invasive parathyroidectomy (MIP) is a surgical procedure that reduces the duration of operation, hospital costs, and hypocalcemia, and shortens the length of hospital stay. This study addressed the important procedural details of the radioguided occult lesion localization (ROLL)-MIP technique and evaluated the consequences of the learning curve from a series of patients.

Patients and Methods

A total of 80 patients who underwent ROLL-MIP for a single parathyroid adenoma were included into this retrospective study. In order to analyze the effect of the learning curve, these subjects were then divided into 2 groups per time period and the operative times were compared. Group A consisted of 22 previously reported patients who served as the control group. Group B consisted of 58 consecutive patients.

Results

Serum calcium and parathyroid hormone (PTH) levels were normalized in all of the patients within 2 days and remained normal during the follow-up period (31 ± 18.5 months). None of the patients who underwent ROLL-guided parathyroidectomy suffered temporary or permanent recurrent laryngeal nerve injuries. Mean operation time (time from incision to excision of the adenoma) was 23 ± 6 min in Group A and 18 ± 7 min in Group B. Mean operative times were significantly shorter in group B.

Conclusion

The success of MIP administered with the ROLL technique in a single adenomatous patient was quite high. This method seems especially valuable in patients with atypically located or small adenomas.

Atypical parathyroid adenoma: clinical and anatomical pathologic features

BACKGROUND

Primary hyperparathyroidism is an endocrine pathology that affects calcium metabolism. Patients with primary hyperparathyroidism have high concentrations of serum calcium or high concentrations of parathyroid hormone, or incorrect parathyroid hormone levels for serum calcium values. Primary hyperparathyroidism is due to the presence of an adenoma/single-gland disease in 80-85%. Multiple gland disease or hyperplasia accounts for 10-15% of cases of primary hyperparathyroidism. Atypical parathyroid adenoma and parathyroid carcinoma are both responsible for about 1.2-1.3% and 1% or less of primary hyperparathyroidism, respectively.

METHODS

We performed a retrospective cohort study and enrolled 117 patients with primary hyperparathyroidism undergoing minimally invasive parathyroidectomy. Histological and immunohistochemical examination showed that 107 patients (91.5%) were diagnosed with typical adenoma (group A), while 10 patients (8.5%) were diagnosed with atypical parathyroid adenoma (group B). None of the patients were affected by parathyroid carcinoma.

RESULTS

Significant statistical differences were found in histological and immunohistochemical parameters as pseudocapsular invasion (p <  0.001), bands of fibrosis (p <  0.001), pronounced trabecular growth (p <  0.001), mitotic rates of > 1/10 high-power fields (HPFs) (p <  0.001), nuclear pleomorphism (p = 0.036), thick capsule (p <  0.001), Ki-67+ > 4% (p <  0.001), galectin-3 + (p = 0.002), and protein gene product (PGP) 9.5 + (p = 0.038).

CONCLUSIONS

Atypical parathyroid adenoma is a tumor that has characteristics both of typical adenoma and parathyroid carcinoma. The diagnosis is reached by excluding with strict methods the presence of malignancy criteria. Atypical parathyroid adenoma compared to typical adenoma showed significant clinical, hematochemical, histological, and immunohistochemical differences. We did not find any disease relapse in the 10 patients with atypical parathyroid adenoma during 60 months of follow-up time.

18F-choline PET/4D CT in hyperparathyroidism: correlation between biochemical data and study parameters

BACKGROUND

Hyperparathyroidism (HPT) is characterised by increased levels of parathyroid hormone (HPT), surgical excision being the only definitive curative option. After establishing the need for surgery, it is essential to identify the parathyroid glands in the preoperative period to use a minimally invasive approach. Negativity and / or discrepancy in first-line studies (ultrasound and Tc-99m MIBI parathyroid scintigraphy) require more accurate images to reduce the likelihood of bilateral cervical exploration or reintervention.

OBJECTIVES

a) To demonstrate the sensitivity of ¹⁸F-fluorocholine (¹⁸F-choline) positron emission tomography (PET)/4D computed tomography (4D CT) in HPT. b) To check whether there is a correlation between calcaemia and preoperative PTH versus size and early and late SUVmax (Standardized Uptake Value) of the gland, determined by ¹⁸F-choline PET/4D CT and c) to study the behaviour of parathyroid lesions with intravenous contrast (IV).

MATERIAL AND METHODS

A total of 28 patients were included between 2016 and 2019 in a single institution. Prospective observational cohort study. Correlations were analysed using Pearson's coefficient for variables with normal distribution and Spearman (rho) for those with non-normal distribution. Anatomopathological analysis was the benchmark standard to determine sensitivity was. A p<.05 was interpreted as significant. STATA 13 software was used.

RESULTS

Of the 28 patients who underwent ¹⁸F-choline PET/4D CT, 18 were operated. Of the 26 lesions diagnosed by ¹⁸F-choline PET/4D CT as suggestive of parathyroid lesions, 23 corresponded to glandular disease (adenoma or hyperplasia) establishing a sensitivity of 88.5%. There was a correlation between the patient's preoperative PTH and the maximum size of the gland on ¹⁸F-choline PET/4D CT. (Spearman=.66; p=.0014). The parathyroid lesions showed, in addition to IV contrast enhancement, distinctive behavioural characteristics identified as highly suggestive.

CONCLUSIONS

18F-choline PET/CT 4D is an anatomical and functional study with high sensitivity in patients with HPT with negative or discrepant first-line studies. Preoperative PTH showed a correlation with maximum gland size on ¹⁸F-choline PET/CT 4D. Parathyroid lesions behave in a highly suggestive way and are enhanced by IV contrast.

The Effectiveness of Preoperative Ultrasonography and Scintigraphy in the Pathological Gland Localization in Primary Hyperparathyroidism Patients

OBJECTIVES

Primary hyperparathyroidism (pHPT) is a common disease, and its curative treatment is surgical. Nowadays, preoperative localization studies have become standard before surgical treatment, and the first stage imaging methods are ultrasonography and/or scintigraphy. With the contribution of these studies to the localization of the pathological gland, focused surgery has become the first standard of choice. In this study, we aimed to evaluate the efficacy of ultrasonography and scintigraphy in the preoperative localization of the pathologic gland or glands in patients who underwent surgical treatment and cure for pHPT.

METHODS

In this study; the data of the biochemically diagnosed pHPT patients, who had Tc 99m-MIBI scintigraphy and/or ultrasonography for localisation preoperatively, were evaluated retrospectively. The lesion, which was positive in USG or scintigraphy for localization, was evaluated according to the neck side or neck quadrant, and the results were compared with intraoperative localization findings. The effectiveness of both methods and combinations was evaluated with the localization rates, sensitivity and positive predictive values (PPV). The three methods were compared with the Youden index (J).

RESULTS

The mean age of 380 patients included in this study was 54.8±12.8 years (20-83). Three hundred eight of them were female, and 72 were male. Scintigraphy was performed in 339 patients, USG was performed in 344 patients, and both USG and scintigraphy were performed in 306 patients. One hundred twenty patients (32%) underwent bilateral neck exploration (BNE), and 260 patients (68.4%) underwent minimally invasive parathyroidectomy (MIP) (unilateral exploration or focused surgery). Single adenoma was detected in 358 (94%), double adenoma in 10 (3%) and hyperplasia in 12 (3%) patients.Localization rates of USG, scintigraphy, USG and scintigraphy combinations were 53%, 74%, 75%; their sensitivity was 56%, 85%, 89%; PPDs were 90%, 86%, 83%. The efficiency of scintigraphy is higher than USG (J: 0.743 vs 0.527). The contribution of scintigraphy to USG in combination with USG was limited (J: 0.743 vs 0.754).The localization rates of USG, scintigraphy, USG and scintigraphy combinations were 46%, 64%, 66%; their sensitivity was 51%, 83%, 88%; PPDs were 79%, 74%, 73%. The efficiency of scintigraphy is higher than that of USG (J: 0.64 vs 0.427). The contribution of scintigraphy to USG in combination with USG was limited (J: 0.64 vs 0.66).

CONCLUSION

In patients with pHPT, scintigraphy is a more effective method for USG as the first step preoperative imaging and should be preferred as the first method if there is no contraindication. A combination of scintigraphy with USG may contribute minimally to the efficacy of scintigraphy. It may be advantageous for early detection of the pathologic gland in patients with incompatible two imaging and initiating surgery on the positive side of the first scintigraphy. Scintigraphy and USG methods may allow successful MRP surgery in the majority of patients with pHPT.

Actual role of color-doppler high-resolution neck ultrasonography in primary hyperparathyroidism: a clinical review and an observational study with a comparison of 99mTc-sestamibi parathyroid scintigraphy

PURPOSE

Primary hyperparathyroidism (PHPT) is a frequent endocrine pathology that has surgical treatment as its only decisive measure. High-Resolution Neck Ultrasonography with color-Doppler (CDHR-NUS) and 99mTechnetium-SestaMIBI Parathyroid Scintigraphy (99mTc-MIBI PS) are the two instrumental exams more commonly used in the preoperatory localization of pathologic parathyroids. The aim of this observational study was to outline-in accordance with the latest scientific literature-the precise role of CDHR-NUS in the environment of PHPT, comparing it with that of Parathyroid Scintigraphy.

METHODS

136 patients operated on for PHPT and underwent CDHR-NUS and 99mTc-MIBI PS preoperatively. The CDHR-NUS was carried out by an expert medical sonographer. The results of the two methods were compared between each other and with the results of the operative act for the evaluation of accordance and diagnostic performances.

RESULTS

PHPT is prevalently due to monoglandular pathology (SGD). The parallel use of CDHR-NUS and of 99mTc-MIBI PS does not determine a significant increase in diagnostic accuracy. The preoperative accordance evaluation between the two methods does not exclude the presence of multiglandular pathology (MGD) with certainty.

CONCLUSIONS

CDHR-NUS is an accurate as well as cost-effective method; its role as a main and eventual unique preoperative localization method in patients affected by PHPT is confirmed. In the presence of expert medical sonographers, the sequential use of the two methods is retained correct and their use in parallel is neither justified nor cost-effective. The preoperative accordance evaluation between the two methods is neither necessary nor indispensable.

American Head and Neck Society Endocrine Surgery Section update on parathyroid imaging for surgical candidates with primary hyperparathyroidism

Health care consumer organizations and insurance companies increasingly are scrutinizing value when considering reimbursement policies for medical interventions. Recently, members of several American Academy of Otolaryngology-Head & Neck Surgery (AAO-HNS) committees worked closely with one insurance company to refine reimbursement policies for preoperative localization imaging in patients undergoing surgery for primary hyperparathyroidism. This endeavor led to an AAO-HNS parathyroid imaging consensus statement (https://www.entnet.org/content/parathyroid-imaging). The American Head and Neck Society Endocrine Surgery Section gathered an expert panel of authors to delineate imaging options for preoperative evaluation of surgical candidates with primary hyperparathyroidism. We review herein the current literature for preoperative parathyroid localization imaging, with discussion of efficacy, cost, and overall value. We recommend that planar sestamibi imaging, single photon emission computed tomography (SPECT), SPECT/CT, CT neck/mediastinum with contrast, MRI, and four dimensional CT (4D-CT) may be used in conjunction with high-resolution neck ultrasound to preoperatively localize pathologic parathyroid glands. PubMed literature on parathyroid imaging was reviewed through February 1, 2019.

The prevalence and anatomy of parathyroid glands: a meta-analysis with implications for parathyroid surgery

Purpose

The anatomy of parathyroid glands (PTG) is highly variable in the population. The aim of this study was to conduct a systematic analysis on the prevalence and location of PTG in healthy and hyperparathyroidism (HPT) patients.

Methods

An extensive search of the major electronic databases was conducted to identify all studies that reported relevant data on the number of PTG per patient and location of PTG. The data was extracted from the eligible studies and pooled into a meta-analysis.

Results

The overall analysis of 26 studies (n = 7005 patients; n = 23,519 PTG) on the number of PTG showed that 81.4% (95% CI 65.4–85.8) of patients have four PTG. A total of 15.9% of PTG are present in ectopic locations, with 11.6% (95% CI 5.1–19.1) in the neck and 4.3% (95% CI 0.7–9.9) in mediastinum. The subgroup analysis of ectopic PTG showed that 51.7% of ectopic PTG in the neck are localized in retroesophageal/paraesophageal space or in the thyroid gland. No significant differences were observed between the healthy and HPT patients and cadaveric and intraoperative studies.

Conclusions

Knowledge regarding the prevalence, location, and anatomy of PTG is essential for surgeons planning for and carrying out parathyroidectomies, as any unidentified PTG, either supernumerary or in ectopic location, can result in unsuccessful treatment and need for reoperation.

Electronic supplementary material

The online version of this article (10.1007/s00423-019-01751-8) contains supplementary material, which is available to authorized users.

Correlation of surgeon-performed parathyroid ultrasound with the Perrier classification and gland weight

BACKGROUND

Ultrasound localisation of parathyroid glands correlates with gland weight. We hypothesise that gland identification is also dependent on anatomical location. Perrier et al. have described a uniform and reliable nomenclature for parathyroid locations. We aimed to correlate surgeon-performed ultrasound (SUS) with intra-operative Perrier classification and gland weight.

METHODS

Review of a prospectively maintained single operator SUS database of 194 patients referred with non-familial primary hyperparathyroidism (PHPT) at a tertiary centre between 2010 and 2015. Patients underwent MIBI localisation as well as on table SUS. Intra-operative pathological gland locations were classified according to the Perrier nomenclature.

RESULTS

Mean weight of pathological glands found and missed by SUS was 1.07 ± 0.1 g and 0.48 ± 0.08 g respectively (p = 0.0001, unpaired t test). The weight of glands identified was greater than that of missed glands for each of the Perrier locations (p < 0.001, Mann-Whitney). The proportion of pathological glands found at each Perrier location varied significantly (p < 0.0001, Chi Square); so we find proportionally more B-, D-, E- and F-type glands and miss more A- and C-type glands. The median weight of glands missed on SUS varied significantly across the Perrier groups (Kruskal-Wallis, p = 0.0034) and suggests that SUS can miss quite large glands (> 0.5 g) in locations B, C and F; whereas missed glands in locations A, D and E were all small (< 0.5 g).

CONCLUSION

Whilst gland identification correlates well with gland weight, anatomical location has a significant impact on failure of localisation irrespective of gland weight. For the surgeon operating on PHPT patients with negative US localisation, particular attention should be paid to locations C, D and A as these are the sites where pathological glands are most often missed on pre-operative US.

A rural perspective on minimally invasive parathyroidectomy: optimal preoperative imaging and patient outcomes

BACKGROUND

Our retrospective review of prospectively collected data evaluated the efficacy of minimally invasive parathyroidectomy (MIP) and compared preoperative imaging modalities in a rural referral centre.

METHODS

Patients with a diagnosis of primary hyperparathyroidism underwent surgeon-performed ultrasound (SUS) and technetium-99 m sestamibi (MIBI). Radiologist-performed ultrasound (RUS) was sought when the diagnosis remained in doubt. Four-dimensional computed tomography (4DCT) first replaced RUS in mid-2014, then MIBI as a frontline modality in 2015. MIP was conducted if possible and bilateral neck exploration (BNE) when localization remained doubtful. Treatment was evaluated by histopathology and serum parathyroid hormone and calcium levels at 6 weeks.

RESULTS

A total of 122 of 165 (73.9%) glands were removed by MIP and 43 of 165 (26.1%) by BNE. Of 15 cases with non-localizing preoperative investigations, one patient had a negative BNE. A total of 160 of 165 (97.0%) patients underwent a successful operation, with five (3.0%) suffering persistent post-operative hypercalcaemia. SUS had a sensitivity of 79.4% (131/165) and a positive predictive value (PPV) of 97.0% (131/135). MIBI had a sensitivity of 60.0% (81/135) and a PPV of 95.3% (81/85). RUS produced a sensitivity of 65.5% (76/116) and PPV of 98.7% (76/77). When used as a second-line modality, 4DCT had a sensitivity of 76.9% (10/13) and PPV of 100%. The sensitivity and PPV were 85.7% (18/21) and 94.7% (18/19) after 4DCT's promotion to first-line use.

CONCLUSION

MIP can be safely performed in rural centres of adequate volume. We recommend that operations be guided by SUS with routine use of an adjunctive modality. Our study has seen 4DCT replace MIBI in this regard.

Hungry bone syndrome

PURPOSE OF REVIEW

In the United States, the number of parathyroidectomies among patients with chronic dialysis has remained stable in the last decade. A fall in serum calcium concentration is common postparathyroidectomy in patients with hyperparathyroidism, which usually resolves in 2-4 days. A severe drop in serum total calcium concentration less than 2.1 mmol/L and/or prolonged hypocalcemia for more than 4 days postparathyroidectomy is called hungry bone syndrome (HBS). Concomitant hypophosphatemia, hypomagnesemia, and hyperkalemia can be seen. Hypocalcemia and hypophosphatemia can persist for months to years. In contemporary clinical practice, HBS may be more commonly seen in patients with secondary compared to primary hyperparathyroidism. Preoperative radiological changes in bone, elevated serum alkaline phosphatase and parathyroid hormone (PTH) levels, and high numbers of osteoclasts on bone biopsy may identify patients at risk. Treatment consists of high-dose oral calcium and calcitriol supplementation. A low-dose pamidronate infusion 1-2 days prior to surgery may prevent HBS.

RECENT FINDINGS

Recent in-vitro studies reported net calcium movement into bone because of a sudden fall in serum PTH level after a prolonged period of elevation. This supports a previous hypothesis that a sudden drop in serum PTH level after surgery results in the unopposed action of osteoblasts and influx of calcium into bone.

SUMMARY

Incidence of HBS and its association with morbidity and mortality remains unclear in contemporary clinical practice. It is more common to encounter HBS in chronic dialysis patients with secondary hyperparathyroidism than those with primary hyperparathyroidism that undergo parathyroidectomies. Use of bisphosphonates to prevent HBS should be explored in future studies.

Sensitivity of 3-Dimensional Sonography in Preoperative Evaluation of Parathyroid Glands in Patients With Primary Hyperparathyroidism

OBJECTIVES

Preoperative localization of parathyroid adenomas in patients with primary hyperparathyroidism facilitates targeted surgery. We assessed the sensitivity of 3-dimensional (3D) sonography for preoperative localization of abnormal parathyroid glands.

METHODS

We conducted a retrospective review of patients who underwent parathyroidectomy for primary hyperparathyroidism at a single site at our institution. We compared preoperative 2-dimensional (2D) sonography, 3D sonography, and sestamibi scans with final gland localization at surgery. Two readers reviewed the sonograms to assess inter-reader variability.

RESULTS

From January 2010 through April 2015, 52 patients underwent parathyroidectomy after preoperative 2D sonography, 3D sonography, and sestamibi scans. Three-dimensional sonography had sensitivity of 88-92% compared with 69-71% for 2D sonography for gland localization. In patients in whom sonography and sestamibi scans localized abnormalities to the same side, the sensitivities were 100% (43 of 43) for 3D sonography and 96% (48 of 50) for 2D sonography. Three-dimensional sonography had significantly higher sensitivity for localization of glands smaller than 500 mg compared with 2D sonography (88% versus 58%; P = .012). There was better inter-reader agreement between the radiologists when using 3D sonography (κ = 0.65) compared with 2D sonography (κ = 0.41).

CONCLUSIONS

We found a significantly higher sensitivity and better inter-reader agreement for 3D sonography compared with 2D sonography for preoperative identification of abnormal parathyroid glands, especially among smaller glands.

Automatic identification of parathyroid in optical coherence tomography images

BACKGROUND AND OBJECTIVE

The identification and preservation of parathyroid is a major problem in thyroid surgery. In order to solve this problem, optical coherence tomography was involved as a real-time, non-invasive high-resolution imaging technique. This study demonstrated an effective and fast method to distinguish parathyroid tissue from thyroid, lymph node, and adipose tissue in their ex vivo optical coherence tomography (OCT) images automatically.

METHODS

OCT images were obtained from parathyroid, thyroid, lymph node, and adipose tissue, respectively. A classification and an identification system based on texture features analysis and back propagation artificial neural network (BP-ANN) were established to classify the four types of tissue and identify each of the four types automatically.

RESULTS

A total of 248 OCT images were taken from 16 patients undergoing thyroidectomy. The accuracy of classification for parathyroid, thyroid, lymph node, and adipose were 99.21, 98.43, 97.65, and 98.43%, respectively.

CONCLUSION

The proposed automatic identification method is capable of distinguishing among parathyroid, thyroid, lymph, and adipose automatically and effectively. Compared with the identification results of human, it has a better accuracy and reliability. For identifying parathyroid from the other entities, it has a satisfying performance. Lasers Surg. Med. 49:305-311, 2017. © 2017 Wiley Periodicals, Inc.

Clinical Presentation, Management, and Outcomes of Primary Hyperparathyroidism during Pregnancy

BACKGROUND

Primary hyperparathyroidism (pHPT) in pregnancy is a rare event, but it poses a significant risk to mothers and fetuses. The optimal treatment strategy remains controversial.

METHODS

We present a consecutive series of twelve pregnant women with pHPT.

RESULTS

Twelve women were diagnosed with pHPT during pregnancy or in the postpartum period. Four of them presented no symptoms or mild symptoms. Four patients experienced serious complications, including hypercalcaemic crisis, acute pancreatitis, and eclampsia. Another four patients were identified postpartum as the result of neonatal convulsion with hypocalcaemia. Minimally invasive parathyroidectomy (MIP) under cervical plexus block was successfully performed in 11 of them during pregnancy or postpartum. The serum levels of ionized calcium and intact parathyroid hormone (iPTH) were much higher in patients with severe complications in this cohort than those in the group of patients with no symptoms or mild symptoms and patients who were diagnosed postpartum.

CONCLUSIONS

MIP under cervical plexus block might be a safe and effective treatment for pregnant women with pHPT. Even though both conservative and surgical treatments are applicable for most mothers and fetuses with asymptomatic and mild hyperparathyroidism, serious complications may have catastrophic consequences for both.

Focused parathyroidectomy without intraoperative parathormone testing is safe after pre-operative localization with 18F-Fluorocholine PET/CT

A focused surgical approach based on pre-operative localization replaced the classical four-gland exploration in patients with primary hyperparathyroidism (PHP). Sestamibi scanning and ultrasound are most often used localization modalities with reported sensitivity of 54-100% for identification of single gland disease. The aim of this study was to analyze the results of pre-operative localization with ¹⁸F-Fluorocholine PET/CT (FCh-PET) in patients with PHP. A retrospective review of 151 patients with PHP who underwent surgery after pre-operative localization with FCh-PET was performed. Only a focused parathyroidectomy without ioPTH testing had been done in patients with single adenoma on FCh-PET. Primary outcome was operative failure, defined as persistent PHP. According to pre-operative FCh-PET 126 (83,4%) patients had single adenoma, 22 (14,5%) multiglandular disease and the test was negative in only two patients. Intraoperative failure experienced 4/126 patients (3,3%) with single adenoma. Removed parathyroid glands were normal in three and hyperplastic in one patient with intraoperative failure. A limited bilateral neck exploration with ioPTH testing was used in 14/22 patients with double adenoma and a classical four-gland exploration without ioPTH testing was used in 8/22 patients with more than two pathological glands according to pre-operative FCh-PET. Intraoperative failure experienced 2/22 patients (9,1%). In two patients with negative FCh-PET a classical four-gland exploration without ioPTH testing was used and one experienced intraoperative failure. A preoperative localization with FCh-PET is a reliable test in patients with PHP. Patients with a single adenoma on FCh-PET can safely undergo a focused parathyroidectomy without ioPTH testing.

Localization of Parathyroid Adenoma With Real-Time Ultrasound: Freehand SPECT Fusion

Preoperative localization of parathyroid adenoma in primary hyperparathyroidism gains in importance as there is a trend toward minimally invasive parathyroid surgery. Besides MRI, 4-dimensional CT, PET/CT, invasive-selective venous sampling, or angiography, both ultrasound and scintigraphy are standard of care for lesion localization. Here we report on a 53-year-old woman with suspicion of primary hyperparathyroidism using real-time fusion of scintigraphic (freehand SPECT) and ultrasound imaging for adenoma localization. Real-time fusion of ultrasound and freehand SPECT allowed noninvasive dedicated metabolic and anatomic adenoma localization and treatment planning.

Impact of preoperative imaging on surgical approach for primary hyperparathyroidism: Data from single institution in India

CONTEXT

Preoperative localization of parathyroid adenoma is essential in deciding the surgical approach of parathyroidectomy.

AIM

To describe clinical and biochemical profile, evaluate preoperative imaging modalities and surgical approach in patients with primary hyperparathyroidism (PHPT).

METHODOLOGY

This was a retrospective study conducted at the single institution. All patients who underwent evaluation and surgery for PHPT from 2011 to 2015 were included in the study.

RESULTS

A total of 100 patients underwent surgery for PHPT. Mean (standard deviation) age was 51.6 (15.9) years with female to male ratio of 1.7:1. Forty patients had severe symptoms, and sixty had mild to moderate symptoms. The sensitivity of technetium-99m hexakis (2-methoxyisobutylisonitrile) (MIBI) scan and ultrasonography (USG) neck in identifying abnormal parathyroid gland was 93% (93/100) and 98% (98/100), respectively. The MIBI scan results of 90/93 (96.7%) patients corresponded with their surgical findings whereas preoperative USG findings of 96/98 patients (98%) showed correlation with operative findings. Intraoperative intact parathyroid hormone (IOPTH) levels at 10 min postexcision were measured in forty patients (minimally invasive parathyroidectomy = 38, bilateral neck exploration = 1, and unilateral neck exploration = 1). All patients except two had <50% fall in IOPTH. Adenoma weight was positively correlated with preoperative intact PTH.

CONCLUSION

We found that USG has higher sensitivity (98%) than MIBI scan (93%) in localizing abnormal parathyroid gland. Moreover, USG had a higher preoperative localization accuracy (93%) than MIBI scan (90%), allowing to choose an appropriate surgical approach. A higher proportion of patients (60%) had mild/asymptomatic form of PHPT.

Patterns of disease in patients at a tertiary referral centre requiring reoperative parathyroidectomy

INTRODUCTION

Reoperative parathyroidectomy is required when there is persistent or recurrent hyperparathyroidism following the initial surgery (at least 5% of parathyroidectomies nationally). By convention, 'persistent disease' is defined as the situation where the patient has not been cured by the first operation. The term 'recurrent hyperparathyroidism' is used when the patient was confirmed to be biochemically cured for six months from the first operation but has hyperparathyroidism after this date. Reoperative surgery is associated with higher rates of postoperative complications as well as a greater rate of failure to cure. The aim of our study was to review our departmental experience of reoperative parathyroidectomy, with a view to identify patterns of disease persistence and recurrence.

METHODS

Using a departmental database, patients were identified who had undergone reoperative parathyroidectomy between 2006 and 2014. All the pre, intra and postoperative information was documented including the operative note so as to record the location of the abnormal parathyroid gland found at reoperation.

RESULTS

Almost two-thirds (63%) of patients had negative, equivocal or discordant conventional imaging so secondary investigative tools were required frequently. The majority of abnormal glands were found in eutopic locations. The most common locations for ectopic glands were intrathyroidal, mediastinal and intrathymic. A third (33%) of the patients had multigland disease and over a quarter (28%) had coexisting thyroid disease.

CONCLUSIONS

Persistent hyperparathyroidism represents a challenging patient subgroup for which access to all radiological modalities and intraoperative parathyroid hormone monitoring are required. Patient selection for reintervention is a key determinant in the reoperation cure rate.

MR appearance of parathyroid adenomas at 3 T in patients with primary hyperparathyroidism: what radiologists need to know for pre-operative localization

OBJECTIVES

To identify frequent MRI features of parathyroid adenomas (PTAs) in patients with primary hyperparathyroidism (PHPT) using a fast protocol with a 3 T magnet.

METHODS

Thirty-eight patients with PHPT underwent a 3 T-MR. All patients had positive US and Tc-99 sestamibi, for a total number of 46 PTAs. T2-weighted IDEAL-FSE and T1 IDEAL-sequences, before and after contrast, were performed. Five features of PTAs were recognised: hyperintensity, homogeneous or "marbled" appearance and elongated morphology on T2-sequences; cleavage plane from thyroid gland on T2-outphase; rapid enhancement in post-contrast T1. Image quality for T2-weighted IDEAL FSE and usefulness for IDEAL post-contrast T1-weighted and T2-outphase sequences were also graded.

RESULTS

PTAs were hyperintense in T2-sequences in 44/46 (95.7%), "marbled" in 30/46 (65.2%) and elongated in 38/46 (82.6%) patients. Cleavage plane was observed in 36/46 (78.3%), and rapid enhancement in 20/46 (43.5%) patients. T2-sequences showed both excellent fat suppression and image quality (average scores of 3.2 and 3.1). T2-outphase images demonstrated to be quite useful (score 2.8), whereas, post-contrast T1 images showed a lower degree of utility (score 2.4).

CONCLUSIONS

A fast protocol with 3.0-T MRI, recognising most common features of PTAs, may be used as a second-line method in the preoperative detection of PTAs.

KEY POINTS

3 T MRI protocol based on T2-weighted IDEAL FSE sequences was used. T2-hyperintensity and elongated morphology are common features of PTAs. 3 T MRI could be used in the preoperative detection of PTAs.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Primary hyperparathyroidism in pregnancy leading to hypercalcaemic crisis and uraemic encephalopathy

Primary hyperparathyroidism is rare during pregnancy. Recognition may be challenging as symptoms overlap with those of other common disorders of pregnancy. Furthermore, physiological changes of pregnancy affecting calcium homoeostasis mean awareness of the condition and careful interpretation of results in the light of pregnancy are essential for diagnosis. Maternal complications of primary hyperparathyroidism include nephrolithiasis, pancreatitis, cardiac arrhythmias, hypertension and peptic ulcers. At its most severe, hypercalcaemic crisis may occur, presenting with acute neurological disturbance. Most commonly, the underlying aetiology is a solitary parathyroid adenoma whereby parathyroidectomy is the only cure. A 30-year-old Caucasian woman booked under Consultant care presented at 32 weeks gestation with vomiting and right-sided loin pain. Following presentation, she was diagnosed with renal calculi. She was delivered by caesarean section (CS) due to deterioration in renal function. Post-CS, she had a grand mal seizure. She was found to have hypercalcaemia with underlying hyperparathyroidism.

Intraoperative optical coherence tomography imaging to identify parathyroid glands

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Diagnostic value of endoscopic ultrasonography for preoperative localization of parathyroid adenomas

The most common cause of primary hyperparathyroidism (PHPT) is a single, sporadic parathyroid adenoma. Ultrasonography (US) and (99m)Technetium methoxyisobutylisonitrile ((99m)Tc-MIBI) scintigraphy are the imaging methods most widely used to localize parathyroid adenomas. The purpose of the present study was to determine the diagnostic value and accuracy of endoscopic ultrasonography (EUS) for localizing parathyroid adenoma compared with those of US and (99m)Tc-MIBI scintigraphy. Forty-seven patients with a PHPT diagnosis and who were recommended for surgery were enrolled in this study. An endoscopist who was blinded to the previous US and (99m)Tc-MIBI scintigraphy results performed the EUS in each patient. Thirty-nine female and eight male patients with PHPT were evaluated. The presence of adenoma was confirmed by subsequent postsurgical pathology results. One case was excluded because the histopathological evaluation was compatible with a lymph node, although the lesion was detected using three different imaging modalities preoperatively. The locations of the parathyroid adenomas were correctly documented by US in 39 patients (84.7 %) by (99m)Tc-MIBI scintigraphy in 35 (76.0 %), and by EUS in 44 (95.6 %) of 46 patients. EUS located all 31 adenomas detected previously with US and (99m)Tc-MIBI scintigraphy. EUS also successfully located three adenomas that could not be identified by US and (99m)Tc-MIBI scintigraphy. The positive predictive value and diagnostic accuracy of EUS, US, and (99m)Tc-MIBI were 97.7, 97.7, and 95.6 %; 88.6, 97.5, and 86.9 %; and 77.7, 97.2, 76.0 %, respectively. EUS was preferred as the second step imaging tool for detecting parathyroid adenomas that could not be localized by US and (99m)Tc-MIBI scintigraphy.

Optical coherence tomography as a method to identify parathyroid glands

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Surgical management of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a common endocrine disorder in which the inappropriate elevation in serum parathyroid hormone level results in hypercalcemia. Most cases are caused by a single adenomatous parathyroid gland and less than 15% are caused by multiglandular disease. The incidence of PHPT appears to be increasing. More patients are being identified earlier and often before symptoms develop. Parathyroidectomy is the only definitive management; with it, the patient can achieve biochemical homeostasis and symptom relief, and sequelae are prevented. Even for asymptomatic patients with PHPT, there is a growing trend to recommend early surgical intervention. Controversy continues regarding the role of and reliance on various technologies, such as preoperative localization imaging, intraoperative parathyroid hormone level measurements, and minimally invasive surgery. Although both traditional bilateral 4-gland exploration and targeted approaches are accepted surgical techniques, there is a growing trend in unilateral targeted operations often using these technologies. Regardless of surgical approach, the expected success rate is greater than 95%. This article provides an overview of the contemporary surgical management of PHPT.

Imaging techniques in parathyroid surgery for primary hyperparathyroidism

As more patients present with the incidental diagnosis of primary hyperparathyroidism due to biochemical screening, treatment guidelines have been developed for the treatment of hyperparathyroidism. Management of primary hyperparathyroidism has evolved in recent years, with considerable interest in minimally invasive approaches. Successful localization of the diseased gland(s) by nuclear imaging and anatomical studies, along with rapid intraoperative parathyroid hormone assay, has allowed for focused and minimally invasive surgical approaches. Patients in whom the localization studies have identified single-gland adenoma or unilateral disease are candidates for such focused approaches instead of the traditional approach of bilateral exploration. These imaging techniques have also been critical in the successful management of patients with persistent or recurrent disease.

The impact of surgeon-based ultrasonography for parathyroid disease on a British endocrine surgical practice

INTRODUCTION

Surgeon-based ultrasonography (SUS) for parathyroid disease has not been widely adopted by British endocrine surgeons despite reports worldwide of accuracy in parathyroid localisation equivalent or superior to radiology-based ultrasonography (RUS). The aim of this study was to determine whether SUS might benefit parathyroid surgical practice in a British endocrine unit.

METHODS

Following an audit to establish the accuracy of RUS and technetium sestamibi (MIBI) in 54 patients, the accuracy of parathyroid localisation by SUS and RUS was compared prospectively with operative findings in 65 patients undergoing surgery for primary hyperparathyroidism (pHPT).

RESULTS

The sensitivity of RUS (40%) was below and MIBI (57%) was within the range of published results in the audit phase. The sensitivity (64%), negative predictive value (86%) and accuracy (86%) of SUS were significantly greater than RUS (37%, 77% and 78% respectively). SUS significantly increased the concordance of parathyroid localisation with MIBI (58% versus 32% with RUS).

CONCLUSIONS

SUS improves parathyroid localisation in a British endocrine surgical practice. It is a useful adjunct to parathyroid practice, particularly in centres without a dedicated parathyroid radiologist, and enables more patients with pHPT to benefit from minimally invasive surgery.

Preoperative parathyroid needle localization: a minimally invasive novel technique in reoperative settings

Background. Reoperative parathyroid surgery for primary hyperparathyroidism can be challenging. Numerous preoperative localization techniques have been employed to facilitate a more focused surgical exploration. This paper describes a novel, minimally invasive, and highly successful method of parathyroid localization. Methods. Patients with recurrent or persistent primary hyperparathyroidism underwent parathyroidectomy following CT scan or ultrasound-guided wire localization of the parathyroid. Accurate placement was confirmed by fine-needle aspiration with immunocytochemistry or PTH washout. The guide wire was left in situ to guide surgical excision of the gland. Curative resection was established by monitoring intact serum PTH levels after excision of the adenoma. Results. All ten patients underwent successful redo-targeted parathyroidectomy. Nine of the ten patients were discharged on the day of surgery. One patient was observed overnight due to transient postoperative hypocalcemia, which resolved with calcium supplementation. Conclusion. Placement of a localization wire via preoperative high-resolution ultrasound or CT can expedite reoperative parathyroid surgery. It allows identification of parathyroid adenoma via a minimally invasive approach, especially in cases where a sestamibi scan is inconclusive.

Endoscopic neck surgery

Endoscopic surgery in the neck was attempted in 1996 for performing parathyroidectomy. A similar surgical technique was used for performing thyroidectomy the following year. Most commonly reported endoscopic neck surgery studies in literature have been on thyroid and parathyroid glands. The approaches are divided into two types i.e., the total endoscopic approach using CO(2) insufflation and the video-assisted approach without CO(2) insufflation. The latter approach has been reported more often. The surgical access (port placements) may vary-the common sites are the neck, anterior chest wall, axilla, and periareolar region. The limiting factors are the size of the gland and malignancy. Few reports are available on endoscopic resection for early thyroid malignancy and cervical lymph node dissection. Endoscopic neck surgery has primarily evolved due to its cosmetic benefits and it has proved to be safe and feasible in suitable patients with thyroid and parathyroid pathologies. Application of this technique for approaching other cervical organs such as the submandibular gland and carotid artery are still in the early experimental phase.

A meta-analysis of preoperative localization techniques for patients with primary hyperparathyroidism

BACKGROUND

Reported accuracy of preoperative localization imaging for primary hyperparathyroidism (pHPT) varies. The purpose of this study is to determine the accuracy of ultrasound, sestamibi-single photon emission computed tomography (SPECT), and four-dimensional computed tomography (4D-CT) as preoperative localization strategies.

METHODS

A meta-analysis was performed of studies investigating the accuracy of ultrasound, sestamibi-SPECT, and 4D-CT for preoperative localization in pHPT. Electronic databases were systematically searched, and two independent reviewers reviewed results using specific criteria. Study quality was assessed using a validated measure for diagnostic imaging studies. Study heterogeneity and pooled results were calculated.

RESULTS

43 studies met criteria for inclusion, and data were available for extraction in 19 ultrasound, 9 sestamibi-SPECT, and 4 4D-CT studies. Ultrasound had pooled sensitivity and positive predictive value (PPV) of 76.1% (95% CI 70.4-81.4%) and 93.2% (90.7-95.3%), respectively. Sestamibi-SPECT had pooled sensitivity and PPV of 78.9% (64-90.6%) and 90.7% (83.5-96.0%), respectively. Only two 4D-CT studies investigated patients undergoing initial parathyroidectomy. Results suggested sensitivity and PPV of 89.4% and 93.5%, respectively.

CONCLUSIONS

Ultrasound and sestamibi-SPECT are similar in ability to preoperatively localize abnormal parathyroid glands in pHPT. Accuracy may be improved with 4D-CT; however, further investigation is required. Choice of preoperative imaging strategy depends on numerous patient, institutional, and economic factors of which the surgeon must be aware.

Surgeon-performed ultrasound is superior to 99Tc-sestamibi scanning to localize parathyroid adenomas in patients with primary hyperparathyroidism: results in 516 patients over 10 years

BACKGROUND

Surgeon-performed cervical ultrasound (SUS) and 99Tc-sestamibi scanning (MIBI) are both useful in patients with primary hyperparathyroidism (PHPT). We sought to determine the relative contributions of SUS and MIBI to accurately predict adenoma location.

STUDY DESIGN

We performed a database review of 516 patients undergoing surgery for PHPT between 2001 and 2010. SUS was performed by 1 of 3 endocrine surgeons. MIBI used 2-hour delayed anterior planar and single-photon emission computerized tomography images. Directed parathyroidectomy was performed with extent of surgery governed by intraoperative parathyroid hormone decline of 50%.

RESULTS

SUS accurately localized adenomas in 87% of patients (342/392), and MIBI correctly identified their locations in 76%, 383/503 (p < 0.001). In patients who underwent SUS first, MIBI provided no additional information in 92% (144/156). In patients who underwent MIBI first, 82% of the time (176/214) SUS was unnecessary (p = 0.015). In 32 patients SUS was falsely negative. The reason for these included gland location in either the deep tracheoesophageal groove (n = 9) or the thyrothymic ligament below the clavicle (n = 5), concurrent thyroid goiter (n = 4), or thyroid cancer (n = 1). In 13 cases, the adenoma was located in a normal ultrasound-accessible location but was missed by the preoperative exam. In the 32 ultrasound false-negative cases, MIBI scans were positive in 21 (66%). Of the 516 patients, 7.6% had multigland disease. Persistent disease occurred in 4 patients (1%) and recurrent disease occurred in 6 (1.2%).

CONCLUSIONS

When performed by experienced surgeons, SUS is more accurate than MIBI for predicting the location of abnormal parathyroids in PHPT patients. For patients facing first-time surgery for PHPT, we now reserve MIBI for patients with unclear or negative SUS.

Techniques for parathyroid localization with ultrasound

Four-gland parathyroid exploration has been the gold standard for parathyroid surgery until recently. Emphasis is now placed on minimally invasive and focused parathyroidectomy. In conjunction with functional sestamibi scanning, ultrasonography permits accurate localization of enlarged parathyroid glands in the vast majority of patients with hyperparathyroidism. Consequently, ultrasound technology applied to parathyroid pathology facilitates directed surgical therapy and minimally invasive applications. As such, ultrasonography holds great promise as a tool that enables cost-effective and advanced patient care.

Minimally invasive parathyroidectomy

Minimally invasive parathyroidectomy (MIP) is an operative approach for the treatment of primary hyperparathyroidism (pHPT). Currently, routine use of improved preoperative localization studies, cervical block anesthesia in the conscious patient, and intraoperative parathyroid hormone analyses aid in guiding surgical therapy. MIP requires less surgical dissection causing decreased trauma to tissues, can be performed safely in the ambulatory setting, and is at least as effective as standard cervical exploration. This paper reviews advances in preoperative localization, anesthetic techniques, and intraoperative management of patients undergoing MIP for the treatment of pHPT.

4D parathyroid CT as the initial localization study for patients with de novo primary hyperparathyroidism

BACKGROUND

Preoperative localization of parathyroid tumors of primary hyperparathyroidism (pHPT) is required for minimally invasive parathyroidectomy (MIP). Parathyroid four-dimensional computed tomography (4DCT) has mainly been used as an adjunct to other imaging modalities in the remedial setting. 4DCT was evaluated as the initial localization study in de novo patients with pHPT.

MATERIALS AND METHODS

A total of 87 consecutive patients underwent parathyroidectomy for pHPT from August 2008 to November 2009. 4DCT was introduced as the preferred imaging modality instead of sestamibi with SPECT (SeS) in April 2009. Results of the imaging studies [4DCT, SeS, and ultrasonography (US)], operative and, pathologic findings, and biochemical measurements were evaluated.

RESULTS

In this study, 84% of patients (73 of 87) underwent an US, 59.8% (52 of 87) a SeS, and 38.0% (33 of 87) had a 4DCT. 4DCT had improved sensitivity (85.7%) over SeS (40.4%) and US (48.0%) to localize parathyroid tumors to the correct quadrant of the neck (P < 0.005) as well as to localize (lateralize) the parathyroid lesions to one side of the neck (93.9% for 4DCT vs. 71.2% for US and 61.5% for SeS; P < 0.005). 4DCT correctly predicted multiglandular disease (MGD) in 85.7% (6 of 7) patients, whereas US and SeS were unable to detect MGD in any case. All patients achieved cure based on intraoperative parathyroid hormone (PTH) measurements and normalization of intact PTH and S-Ca during follow-up.

CONCLUSIONS

4DCT provides significantly greater sensitivity than SeS and US for precise localization of parathyroid tumors of pHPT. Additionally, it correctly predicted MGD in a majority of patients.