Preoperative evaluation of patients with primary hyperparathyroidism: role of high-resolution ultrasound

4DCT in Discordant Parathyroid Adenoma Scans: Case Series and Meta-Analysis

OBJECTIVE

To evaluate the accuracy of four-dimensional computerized-tomography (4DCT) for localizing parathyroid adenomas (PTAs) in cases with discordant or non-localizing ultrasonography (US) and Technetium-99 sestamibi (MIBI) scans.

DATA SOURCES

Retrospective case series and systematic review.

REVIEW METHODS

A case series and meta-analysis of patients diagnosed with primary hyperparathyroidism and discordant US and MIBI scans who underwent 4DCT prior to surgery. A comprehensive search for all relevant publications in the English literature between December 2006 and March 2022 was conducted for the meta-analysis. Patients undergoing parathyroidectomy between January 2015 and December 2021 were identified from the institutional electronic database for the case series. All studies were analyzed for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the 4DCT adenoma localization capabilities.

RESULTS

Thirteen retrospective studies that included 379 patients and one case series that included 37 patients were identified and analyzed. A per-patient analysis revealed sensitivity for lateralization to the correct side (n = 181) ranging from 80% to 100% with a fixed effects model of 89% (95%confidence interval [CI]: 82%-93%) and a PPV for lateralization ranging from 63%-95% with a random effects model of 87% (95% CI: 77%-95%). Sensitivity of localization to the correct quadrant (n = 172) ranged from 53% to 100% with a random effects model of 90.4% (95% CI: 76%-99%), and the PPV for localization ranged from 52% to 100% with a random effects model of 82% (95% CI: 73%-89%).

CONCLUSION

4DCT enhances imaging capabilities of localizing PTAs in cases of discordant or non-localizing US and MIBI scans.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:2198-2205, 2024.

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.

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.

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.

Ultrasonography: highly accuracy technique for preoperative localization of parathyroid adenoma

OBJECTIVES/HYPOTHESIS

This study evaluates the accuracy of ultrasonography in guided unilateral parathyroidectomy to treat primary hyperparathyroidism.

STUDY DESIGN

Retrospective study.

METHODS

Two hundred fifty-three patients with primary hyperparathyroidism underwent preoperative ultrasonography. Two groups were defined. Group 1 included the patients in whom the preoperative cervical ultrasound localized one abnormal parathyroid gland; these patients underwent unilateral surgical exploration of the neck under local anesthesia. Group 2 included the patients who had a bilateral neck exploration under general anesthesia when the preoperative examination was equivocal or failed to localize the lesion, when concomitant thyroid pathology indicated thyroidectomy, and when justified by the surgical findings.

RESULTS

Sensitivity and positive predictive value of ultrasonography in detecting abnormal parathyroid gland were 96% and 98%, respectively. Cervical ultrasound correctly identified, 96% and 85% of abnormal glands in groups 1 and 2, respectively. The presence of thyroid nodular disease did not affect ultrasonographic accuracy. Sonographic examination decreased the operative time of parathyroidectomy to an average of 15 minutes. Mediastinal and retroesophageal localizations of abnormal parathyroid gland adversely affected the accuracy of the ultrasound. No cervical hematoma was noted. Transient recurrent laryngeal nerve palsy occurred in four patients. Twenty-three patients required postoperative calcium supplementation for 2 to 4 months, and all were normocalcemic at follow-up.

CONCLUSIONS

Cervical ultrasound is a reliable preoperative exploration allowing parathyroidectomy via unilateral approach under local anesthesia.

MINIMALLY INVASIVE PARATHYROIDECTOMY USING SURGEON-PERFORMED ULTRASOUND AND SESTAMIBI

BACKGROUND

Surgeon-performed ultrasound (SPU) and (99m)Tc-sestamibi (SM) scanning can be used alone or in combination in patients with primary hyperparathyroidism to select cases suitable for minimally invasive parathyroidectomy (MIP). The aim of the study was to evaluate SPU and SM and to determine the reliability they provide the surgeon in planning and carrying out MIP.

METHODS

The study was a prospective analysis of 130 patients with primary hyperparathyroidism who had preoperative localization with SPU and SM at a tertiary referral centre between 2003 and 2006. All ultrasound scans were carried out by one surgeon, followed by correlative sestamibi scan and a further 'on operating table' ultrasound to reassess the lesion and mark the operative site. Selection criteria for MIP were a positive SPU and SM, although a positive SPU or SM allowed the surgeon to focus on the nominated side. SPU and SM localizations were correlated to the operative findings.

RESULTS

One hundred and thirty patients underwent both SPU and SM. There were 97 women and 33 men, with a mean age of 59 years. SPU alone identified the abnormal parathyroid in 103 cases (sensitivity 82%; positive predictive value 96.3%). SM alone identified the abnormal gland in 102 cases (sensitivity 79%; positive predictive value 99%). In 88 patients, the SPU and SM were concordant, and 94% had successful MIP. SPU and SM were both negative in 13 patients, and all these patients had bilateral neck exploration.

CONCLUSION

SPU in the hands of an experienced surgeon in association with sestamibi is a reliable tool for the preoperative localization of parathyroid adenomas and facilitates a minimally invasive procedure.

Intrathyroid Parathyroid Adenoma in Primary Hyperparathyroidism: Can It Be Predicted Preoperatively?

INTRODUCTION

The role of cervical ultrasonography (US)-guided surgery for intrathyroid parathyroid adenoma in primary hyperparathyroidism is rarely reported. The aim of this study was to elucidate the role of cervical US in identifying this entity.

METHODS

From 1996 to 2003, cervical explorations were performed in 178 patients (mean age 57 years) with primary hyperparathyroidism. High-resolution cervical US was performed in all of the patients. Patients' characteristics were reviewed to identify predictive factors for intrathyroid adenoma.

RESULTS

Cervical US identified abnormal parathyroid glands in 163 of 178 patients, with a positive predictive value (PPV) of 100%. Six patients (3.4%) were found to have intrathyroid parathyroid adenomas (two in the superior parathyroid and four in the inferior parathyroid). Cervical US predicted this anomaly in four of six patients (67%) in whom the thyroid gland was not nodular and allowed total enucleation of the adenoma to be performed in three and subtotal thyroid loboisthmectomy in three; these operations were performed uneventfully and rapidly. The PPV in this anomaly was 80%. Thirteen patients required postoperative calcium supplementation for 2 to 4 months, and all were normocalcemic at the time of the last clinic visit, with follow-up varying from 12 to 96 months. On multivariable analysis, no factor predicted intrathyroid localization of parathyroid adenoma.

CONCLUSIONS

The PPV of high-resolution cervical US for identifying an abnormal parathyroid gland was 100% in this series. It was 80% for predicting intrathyroid localization of the adenoma. This method allows us to shorten the operating time by guiding the exploration immediately toward the thyroid gland.

Parathyroid sonography: imaging and intervention

This article reviews the role of high-resolution sonography as an imaging modality for the diagnosis and treatment of patients with parathyroid disease. Included is a discussion of sonographic anatomy and technique, disease processes of the parathyroid glands and their sonographic appearances, preoperative imaging, and the use of sonography as a guide for diagnostic and therapeutic intervention in parathyroid disease.

Impact of Gland Morphology and Concomitant Thyroid Nodules on Preoperative Localization of Parathyroid Adenomas

OBJECTIVES

Primary hyperparathyroidism (pHPT) is a common endocrine disease. The aim of this study was to assess the effect of the presence of thyroid nodules, adenoma weight, and ectopic localization on the sensitivity of different imaging studies in patients with hyperparathyroidism.

STUDY DESIGN

A series of 125 patients with pHPT who underwent low-frequency ultrasonography, high-frequency ultrasonography, Thallium-Technetium scintigraphy, sestamibi scintigraphy, and combined technique was reviewed retrospectively. Patients were divided in two groups depending on the presence or absence of thyroid nodules.

RESULTS

The overall sensitivity of low-frequency ultrasonography, high-frequency ultrasonography, Thallium-Technetium scintigraphy, sestamibi scintigraphy, and combined technique was 69%, 89%, 71%, 86%, and 98%, respectively. The sensitivity of these imaging studies was 94%, 100%, 94%, 96%, and 100%, respectively, in our patients with no thyroid nodules but decreased to 54%, 84%, 54%, 81%, and 79%, respectively, in the presence of thyroid nodules. The parathyroid adenoma weight in true-positive imaging studies was significantly higher than those in false-positive and false-negative imaging studies. The numbers of ectopic parathyroid adenomas were found to be higher in the group of parathyroid adenomas undetected with ultrasonography when compared with ultrasonographically detected adenomas.

CONCLUSION

In patients with parathyroid adenoma, the sensitivity of imaging studies correlates with the presence of thyroid nodules, adenoma weight, and ectopic localization.

Rapid Intraoperative Parathyroid Hormone Assay—More than Just a Comfort Measure

BACKGROUND

Minimally invasive radio-guided parathyroidectomy (MIRP) has been embraced as an acceptable therapeutic approach to primary hyperparathyroidism. Preoperative sestamibi scanning has facilitated this technique. Here we evaluate the addition of a rapid intraoperative parathyroid hormone (iPTH) assay for patients undergoing MIRP.

METHODS

A series of 51 patients underwent sestamibi localization of parathyroid glands followed by MIRP for primary hyperparathyroidism. Using peripheral venous samples, iPTH levels were measured prior to gland excision, as well as post-excision at 5, 10, and 15 minutes, taking a 50% reduction in iPTH level as indicative of complete excision. Next, changes in serum iPTH were compared with preoperative and postoperative changes in serum calcium, as well as levels of intraoperative ex-vivo radiation counts taken by hand-held gamma probe.

RESULTS

In this series, a drop of greater than 50% in iPTH levels was observed in 94% of patients (n=48). Moreover, a significant drop in iPTH occurred within 10 minutes of excision in the majority (n=42) of cases (P<0.004). Changes in iPTH were comparable with the therapeutic reduction in calcium levels, as well as with the change in intraoperative ex-vivo gamma counts.

CONCLUSIONS

This study demonstrates that the addition of an iPTH assay to MIRP provides a quick and reliable intraoperative diagnostic modality in confirming correct adenoma removal. Moreover, it precludes the requirement of frozen section.

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

PURPOSE

Solitary adenoma of the parathyroid is the major cause of primary hyperparathyroidism. Many centers advocate a minimally invasive surgical approach, wherein the surgeon explores only a localized area of the neck according to the preoperative imaging evaluation, and the adenoma is resected without histological sampling from the other parathyroid glands. The aim of this study was to evaluate the ability of high-resolution ultrasonography (US) to localize adenomas preoperatively and thereby aid in patient selection for minimal procedures.

METHODS

We reviewed the medical records of 77 consecutive patients who underwent resection of a parathyroid adenoma following ultrasonographic imaging between 2001 and 2002, and we assessed the accuracy of the preoperative localization of the adenomas as well as the efficacy of the minimally invasive procedure.

RESULTS

US correctly localized the adenoma to a specific quadrant of the neck in 87% of the cases and to a specific side of the neck in 94%. Overall, US sensitivity was 89%, with a positive predictive value of 98%. Its sensitivity was not reduced by the presence of nodular disease of the thyroid gland. Success rate for the minimal procedure was 98% (50/51 patients).

CONCLUSIONS

US performed by a skilled operator is a reliable tool for adenoma localization prior to minimally invasive parathyroidectomy. If the US findings are inconclusive, a Tc-sestamibi scan should be used. If there is a high clinical suspicion of adenoma in the presence of negative imaging studies, bilateral neck exploration should be performed.

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.

Accuracy of surgeon-performed ultrasound in parathyroid localization

Ultrasound is one of the preferred modalities for localization of abnormal parathyroids. Accuracy of ultrasound is technician-dependent. This study was undertaken to determine the accuracy of surgeon-performed ultrasound (SPU) for the localization of parathyroid tumors in comparison to radiology-performed ultrasound (RPU) and nuclear scintigraphy (NS). In this series 74 consecutive patients with untreated primary hyperparathyroidism underwent SPU at the initial clinic visit; 21 of these patients did not undergo surgery and are excluded from the analysis. Of the 53 patients remaining, RPU was obtained in 26, and 52 patients underwent NS. Directed parathyroidectomy was performed with use of the intraoperative parathyroid hormone assay (IOPTH). In all, 46 patients had a single adenoma as indicated by IOPTH and final pathology. Two patients had double gland disease, and 5 patients had multi-gland hyperplasia. The sensitivity of SPU was 82% and the specificity was 90% in detecting the diseased glands on the correct side (right versus left). The sensitivity for RPU was 42% and the specificity was 92% (n = 26). The sensitivity of NS was 44% and the specificity was 98% (n = 52). In only one case did RPU or NS detect a gland not found by SPU. SPU can be done with accuracy comparable to other ultrasound series in the literature, and it may be superior to RPU or NS in some institutions. It is important for surgeons to be aware of local institutional expertise when relying on RPU and NS during preoperative evaluation prior to directed parathyroidectomy.

Imaging for primary hyperparathyroidism--what beginners should know

For patients with primary hyperparathyroidism surgical removal of the hyperfunctioning parathyroid gland is curative. With advances in minimally invasive surgery, accurate pre-operative localization of the hyperfunctioning parathyroid tissue is essential to aid successful surgical treatment. The onus of identifying this hyperfunctioning parathyroid tissue therefore falls on imaging techniques such as high-resolution ultrasound, radionuclide imaging, computed tomography and magnetic resonance imaging. This article is not an exhaustive review, and its main aim is to familiarize the general radiologist, trainee radiologists and clinicians with the basics of various imaging techniques and their roles in practical management of patients with primary hyperparathyroidism.

The cost-effectiveness of sestamibi scanning compared to bilateral neck exploration for the treatment of primary hyperparathyroidism

This article presents a cost-effectiveness analysis to determine whether preoperative imaging with Tc99m-sestamibi for detection and treatment of solitary adenomas associated with primary hyperparathyroidism is cost-effective compared with routine bilateral neck exploration.

Ultrasound examination of the parathyroid glands

High-resolution sonography is a significant imaging tool available for evaluation of the parathyroid glands. It works particularly well in concert with nuclear imaging, especially in assisting preoperative localization of parathyroid lesions and in guiding interventional parathyroid procedures. Its limitations relate to anatomic areas not accessible to insonation. In the hands of an experienced examiner, it is a cost-efficient and important adjunct for the endocrine surgeon.

Unilateral and bilateral surgery for parathyroid disease

The principles of successful parathyroid surgery, regardless of the approach, demand a clear understanding of the philosophy behind the surgical exploration. A systematic approach, founded in science and refined by experience, is necessary to achieve long-term, reproducible surgical success. This article discusses the underlying logic and the advantages and disadvantages of the two basic approaches to parathyroid pathology: unilateral and bilateral cervical exploration. The authors do not to advocate a particular technique;instead, they provide a conceptual framework to surgical parathyroid disease upon which more advanced discussion can be built.

Challenges In Neck Ultrasonography: Lymphadenopathy And Parathyroid Glands

OBJECTIVE

To assess the performance of neck ultrasonography (US) in the detection of lymph node lesions metastatic from differentiated thyroid carcinoma (DTC) and the detection of parathyroid adenomas.

METHODS

Neck US was performed in 667 patients with DTC (173 men and 494 women; mean age, 47.7 years). In cases of suspicious neck nodes, US-guided fine-needle aspiration biopsy (US-FNAB) plus measurement of thyroglobulin in the needle washouts (FNAB-Tg) was done. In addition, 75 patients with primary hyperparathyroidism (pHPT) (15 men and 60 women; mean age, 56 years) underwent neck US and sestamibi scintiscanning for localization of parathyroid adenoma. For confirmation of US findings, US-FNAB plus measurement of parathyroid hormone in the needle washouts (FNAB-PTH) was performed. FNAB-PTH was also measured in 129 suspected parathyroid adenomas incidentally detected in a series of 4,129 patients undergoing neck US examination for thyroid disease.

RESULTS

The presence of DTC metastatic lesions was confirmed in 46 of 95 patients with suspicious neck nodes. US sensitivity and specificity were 82.1% and 91.2%, respectively. The positive predictive value (PPV) of US-FNAB + FNAB-Tg was 94.7%. In the 75 patients with pHPT, US followed by US-FNAB + FNAB-PTH showed a higher PPV (97.5%) in comparison with sestamibi scintiscanning (83.7%) in the detection of parathyroid adenoma. A parathyroid adenoma was also incidentally detected in 0.62% of the 4,129 patients undergoing neck US for thyroid disease.

CONCLUSION

US accurately detects DTC neck metastatic lesions and localizes parathyroid adenomas. Moreover, neck US may lead to discovery of parathyroid incidentalomas.

The diagnostic utility of computed tomography for preoperative localization in surgery for hyperparathyroidism

OBJECTIVES/HYPOTHESIS

Successful unilateral or minimal-access parathyroid exploration and reoperative surgery of the parathyroid glands requires accurate preoperative localization of parathyroid disease. Although ultrasound and nuclear imaging techniques have an established role in this regard, the use of computed tomography (CT) for parathyroid exploration is not well understood. The purpose of the present study was to better define the diagnostic utility of CT in preoperative localization of the abnormal gland in surgery for hyperparathyroidism.

STUDY DESIGN

Retrospective cohort study.

METHODS

All parathyroid explorations performed at Oregon Health and Science University (Portland, OR) between 2000 and 2002 were reviewed. The study group was limited to patients with hyperparathyroidism in whom localization failed preoperatively using ultrasound and/or sestamibi scanning and subsequent investigation using CT imaging was performed. Operative, pathological, and imaging reports were then analyzed to assess the accuracy of CT imaging for localizing parathyroid disease.

RESULTS

Twenty-two patients with hyperparathyroidism were investigated preoperatively using CT imaging. Parathyroid exploration was successful in all but one patient, leaving 21 patients in all in the cohort. The majority of cases (67%) were reoperative, and all patients had previously undergone inconclusive ultrasound and/or sestamibi scanning. Computed tomography correctly localized parathyroid disease in 18 (86%) of the 21 patients who underwent successful extirpation of parathyroid disease and was able to identify abnormal glands with equal utility in the neck and the chest.

CONCLUSION

When ultrasound or sestamibi are unsuccessful, CT imaging can provide valuable preoperative localizing information before surgery for hyperparathyroidism, particularly in patients with recurrent or persistent disease.

Preoperative evaluation of parathyroid lesions in patients with concomitant thyroid disease: role of high resolution ultrasonography and dual phase technetium 99m sestamibi scintigraphy

The aim of this study was to evaluate the sensitivity and usefulness of high resolution ultrasonography (US) and dual phase technetium-99m sestamibi (Tc-MIBI) scintigraphy in the preoperative localization of parathyroid lesions in patients with or without thyroid disease and to define the impact of the presence of thyroid disease on these methods. Preoperative US and scintigraphy were performed on 52 patients with primary hyperparathyroidism. Age, gender, preoperative parathyroid hormone level, serum calcium level, serum phosphate level, diameter, location, associated with thyroid abnormality, and results of parathyroid exploration were determined in all patients. The results of US and Tc-MIBI imaging were analyzed and compared with surgical and histopathologic findings. At surgery, 56 parathyroid lesions were found in 52 patients (9 men, 43 women), the parathyroid lesion was solitary (47 adenomas, two hyperplasias), in 2 patients double adenomas were present, in 1 patient three glands was affected by hyperplasia. Twenty-seven patients had concomitant thyroid disease. The overall sensitivity of US and Tc-MIBI scintigraphy was 84% and 73%, respectively. In patients without thyroid disease, the sensitivity of these techniques was 90% and 75%, respectively. In patients with thyroid disease, the sensitivity was 78% and 70%, respectively. In patients with thyroid disease, the combined sensitivity of these techniques was 89%. These results allow the conclusion that, in experienced hands, US is a highly sensitive technique. Especially in patients with no thyroid pathology and typical located gland, US alone should be used as a first step for preoperative localization of parathyroid lesions. When negative, Tc-MIBI scintigraphy is suggested. In patients with concomitant thyroid disease, the combination of US and Tc-MIBI scintigraphy represents a reliable localization technique.

[Diagnostic value of parathyroid localization techniques in surgery for primary hyperparathyroidism]

OBJECTIVES

To determine the accuracy of imaging techniques for localization of nodular lesions of parathyroid glands.

MATERIAL AND METHODS

Seventy one patients were prospectively enrolled and underwent surgical examination for primary hyperparathyroidism. Ultrasonography (US), 201Tl/99mTc parathyroid subtraction scintigraphy and 99mTc MIBI scintigraphy were evaluated.

RESULTS

The sensitivity and specificity for combined 201Tl/99mTc parathyroid subtraction scintigraphy and US for parathyroid adenomas were 72.27% and 89.22% respectively. The combination of 99mTc MIBI scintigraphy and US resulted in improved specificity (93.67%) and positive predictive value (80.39%). The accuracy of the localizing studies was lower for patients with hyperplasia.

CONCLUSIONS

The combination of scintigraphy and US is the best approach for localization of nodules. In most cases, the two techniques are complementary.

Unilateral versus bilateral neck exploration for primary hyperparathyroidism: a prospective randomized controlled trial

OBJECTIVE

To compare unilateral and bilateral neck exploration for primary hyperparathyroidism in a prospective randomized controlled trial.

SUMMARY BACKGROUND DATA

Based on the assumption that unilateral neck exploration for a solitary parathyroid adenoma should reduce operating time and morbidity, a variety of minimally invasive procedures have challenged the idea that bilateral neck exploration is the gold standard for the surgical treatment of primary hyperparathyroidism. However, to date, no open prospective randomized trial has been published comparing unilateral and bilateral neck exploration.

METHODS

Ninety-one patients with the preoperative diagnosis of primary hyperparathyroidism were randomized to unilateral or bilateral neck exploration. Preoperative scintigraphy and intraoperative parathyroid hormone measurement guided the unilateral exploration. Gross morphology and frozen section determined the extent of parathyroid tissue resection in the bilateral group. The primary end-point was the use of postoperative medication for hypocalcemic symptoms.

RESULTS

Eighty-eight patients (97%) were cured. Histology and cure rate did not differ between the two groups. Patients in the bilateral group consumed more oral calcium, had lower serum calcium values on postoperative days 1 to 4, and had a higher incidence of early severe symptomatic hypocalcemia compared with patients in the unilateral group. In addition, for patients undergoing surgery for a solitary parathyroid adenoma, unilateral exploration was associated with a shorter operative time. The cost for the two procedures did not differ.

CONCLUSIONS

Patients undergoing a unilateral procedure had a lower incidence of biochemical and severe symptomatic hypocalcemia in the early postoperative period compared with patients undergoing bilateral exploration. Unilateral neck exploration with intraoperative parathyroid hormone assessment is a valid surgical strategy in patients with primary hyperparathyroidism with distinct advantages, especially for patients with solitary parathyroid adenoma.

Preoperative evaluation of patients with parathyroid adenoma: role of high-resolution ultrasonography

BACKGROUND

Unilateral parathyroid exploration with adenoma removal and identification of a normal parathyroid gland is a controversial surgical approach to the treatment of primary hyperparathyroidism. The aim of this study was to evaluate the ability of high-resolution ultrasonography to localize adenomas preoperatively and to assess the effect of such localization on operative time.

METHODS

One hundred twenty consecutive previously non-operated patients with primary hyperparathyroidism underwent ultrasonography before surgery, which consisted of unilateral neck exploration. The procedure was changed to bilateral exploration when justified by the surgical findings.

RESULTS

The sensitivity and positive predictive value of the ultrasonographic examinations were 89% and 98%, respectively. These results were obtained regardless of the size of the adenoma. No significant difference was found in the presence of thyroid multinodular disease (p =.2). A positive sonographic examination decreased the operative time to an average of 59 minutes. The average size of the adenomas was 19 mm (range, 4-55 mm). A positive and highly statistically significant correlation was found between adenoma size and both preoperative calcium level (p =.01) and parathyroid hormone level (p =.0001).

CONCLUSIONS

In experienced hands, high-resolution ultrasonography can be a cost-effective means of localizing parathyroid adenomas when unilateral neck exploration is considered the acceptable surgical approach.

Pre-operative localization of parathyroid adenomas: a comparison of power and colour Doppler ultrasonography with nuclear medicine scintigraphy

AIM

To compare power and colour Doppler ultrasonography (US) with nuclear medicine scintigraphy (NM) in the preoperative localization of parathyroid adenomas in patients with primary hyperparathyroidism (PHPT).

MATERIALS AND METHODS

Thirty-one patients with biochemical evidence of PHPT underwent pre-operative US and NM for parathyroid adenoma localization. Both studies were interpreted independently without prior knowledge of the other study's findings. All patients had surgical removal of the parathyroid adenoma utilizing standard neck exploration or minimally invasive unilateral surgical techniques with rapid serum assay of circulating parathyroid hormone levels.

RESULTS

All patients had single parathyroid adenomas at surgery. Prospective sensitivities for US, NM and both studies combined were 65%, 68%, and 74%, respectively, with a positive predictive value of 100% each. The adenoma was localized by only one imaging modality in 16% of cases.

CONCLUSIONS

US and NM provide complementary roles in the pre-operative localization of parathyroid adenomas in patients with PHPT.

Accuracy of terminology and methodology in economic analyses in otolaryngology

OBJECTIVE

Economic studies increasingly guide health care resource allocation decisions. Because rigorous adherence to accepted definitions and research techniques is critical to ensure accuracy, we evaluated the terminology and methods of otolaryngology economic analyses.

STUDY DESIGN

A total of 71 articles published from 1990 to 1999 in 6 peer-reviewed otolaryngology journals with terms such as "cost-effective" in their title or representing economic analyses were reviewed for terminology and use of established methodology guidelines.

RESULTS

Over half (35 of 66) of terms such as "cost-effective" were used incorrectly, and 60% of articles (39 of 64) confused "charge" and "cost" data. Eleven percent (7 of 64) of papers specified the perspective of their analysis. About half (17 of 30) reported a summary measure such as a cost-effectiveness ratio. Only one third (23 of 63) performed sensitivity analyses.

CONCLUSION

Adherence to accepted definitions and research methods is inconsistent, although we did note moderate improvements in making the distinction between costs and charges, defining of study perspective, and performing sensitivity analysis.

SIGNIFICANCE

Greater attention to both terminology and methodology can enhance the quality of economic analyses and ultimately improve certain resource allocation decisions.

Ultrasound evaluation of the parathyroid glands in two hypercalcemic cats

Two parathyroid masses were identified using ultrasound in two hypercalcemic cats. The masses were identified as parathyroid adenomas on surgical biopsy. Both parathyroid masses contained hypoechoic regions with distal acoustic enhancement. Both masses were greater than 1.0 cm in diameter.

[Surgery for primary hyperparathyroidism in 1998. Apropos of 66 patients and 3 methods of approach]

STUDY AIM

The aim of this prospective study was to assess the advantages and disadvantages of cervicotomy, selective lateral approach and video-assisted surgery in the treatment of primary hyperparathyroidism (HPT 1).

PATIENTS AND METHODS

During 1998, 66 patients were operated on for HPT 1 in the same center. There were 48 women and 18 men (mean age: 58 years, range: 21-84), familial HPT 1 or MEN1 excluded. The interventions were performed via classical cervicotomy (n = 32), via selective lateral approach (n = 8) and were video-assisted (n = 25). A mediastinal adenoma was removed via cervicotomy and another one via left thoracoscopy. The procedure was associated with intraoperative parathormone (PTH) quick-assay. Calcium testing was controlled before leaving the hospital and 2 months later.

RESULTS

A double adenoma and 65 single adenomas were confirmed by pathological report. Circulating PTH levels, 20 minutes after removal of the adenoma, always decreased significantly. In video-assisted procedures, there were 11 conversions to open cervicotomy (44%) and morbidity consisted of one case of laryngeal nerve paralysis. At the end of the study, all patients except one had a normal calcium level.

CONCLUSION

Video-assisted parathyroidectomy is feasible but requires a preoperative localisation of the adenoma and intraoperative PTH quick-assay. Its main benefit in cervical adenoma is to reduce the scar and in mediastinal adenoma to avoid sternotomy. With the elective approach, results are similar to those of video-assisted surgery and the procedure is much easier to perform. Classical cervicotomy is still the best option in case of previous cervicotomy, of simultaneous thyroidectomy, of negative preoperative imaging and in elderly patients less concerned about cosmetic benefit.

Minimally invasive surgery for primary hyperparathyroidism: a systematic review

BACKGROUND

The aim of the present paper was to systematically review the literature regarding the safety and efficacy of minimally invasive parathyroidectomy techniques in patients with primary hyperparathyroidism. Studies using unilateral or endoscopic exploration following imaging were compared with bilateral open neck exploration.

METHODS

Studies on minimally invasive parathyroid surgery were identified using MEDLINE (1984 to August 1998), EMBASE (1974 to August 1998) and Current Contents (1993 to week 34, 1998). The search terms were ((endoscop* or (minimal* and invasive) or unilateral) and parathyroid). The Cochrane Library was searched from 1966 to issue 3 1998, using the search terms 'parathyroidectomy or parathyroid resection'. Human studies of patients with primary hyperparathyroidism using unilateral or endoscopic exploration were included. Animal studies describing minimally invasive technique development were also included. A surgeon and researcher independently assessed the retrieved articles for their inclusion in the review. Studies directly comparing the unilateral method with bilateral open neck exploration were used to analyse outcomes.

RESULTS

Analysis of data using odds ratios and 95% confidence intervals (CI) indicated a tendency to favour the unilateral technique. These individual studies generally had large CI, however; therefore preference to the unilateral procedure cannot be espoused with certainty. There is also a selection bias due to the strict enrollment criteria for unilateral surgery.

CONCLUSIONS

The proposed role of minimally invasive parathyroid surgery is for patients with primary hyperparathyroidism who have unilateral parathyroid pathology. To assess the safety and efficacy of minimally invasive techniques it is suggested that their introduction be monitored as part of a trial in Australia, from which data should be accrued to a register.

Detection and diagnosis of parathyroid incidentalomas during thyroid sonography

PURPOSE

The aim of our study was to evaluate the incidence of incidentally found parathyroid adenomas (incidentalomas) in patients undergoing sonography of the neck for thyroid disease.

METHODS

A total of 1,686 patients (305 men and 1,381 women) underwent sonography of the neck; the mean age was 49.6 +/- 21.7 years. In 38 patients (2.3%; 7 men and 31 women) with a mean age of 48.7 +/- 14.7 years, hypoechoic, homogeneous, oval nodules (mean volume, 1.0 +/- 0. 9 cm(3)) adjacent to the thyroid parenchyma were observed. All these lesions, compatible with the shape of an enlarged parathyroid gland, underwent ultrasound-guided fine-needle aspiration biopsy (FNAB), with measurement of parathyroid hormone (PTH) and thyroglobulin (Tg) levels in the needle washings (FNAB-PTH and FNAB-Tg). Biochemical screening for hyperparathyroidism was also performed.

RESULTS

Cytologic examination plus FNAB-PTH/FNAB-Tg measurements revealed the presence of cellular material consistent with parathyroid tissue in 9 patients (24%), thyroid tissue in 22 patients (58%), and lymphoid tissue in 4 patients (11%). A tissue diagnosis was not established in 3 patients (8%). Five of 9 patients with parathyroid enlargement had high serum PTH and calcium levels.

CONCLUSIONS

Enlarged parathyroid glands may be incidentally discovered during sonography of the thyroid. In patients with thyroid disease, the positive-predictive value of sonography in the identification of parathyroid tissue was low. Ultrasound-guided FNAB-PTH determination should be carried out when parathyroid adenoma is suspected. The incidental finding of an enlarged parathyroid may or may not be associated with yet undiagnosed hyperparathyroidism.