Surgeon-performed ultrasound: A single institution experience in parathyroid localization

Surgery for nonlocalizing hyperparathyroidism in high volume center

BACKGROUND

Patients with nonlocalizing hyperparathyroidism pose a significant challenge to surgeons when undergoing neck exploration for parathyroidectomy.

METHODS

We evaluated 536 patients that had parathyroidectomy for primary hyperparathyroidism (PHPT) from 2005 to 2018 at a single tertiary academic center, and 155 (29%) had standard nonlocalizing preoperative imaging (negative ultrasound and sestamibi scans).

RESULTS

There were a total of 102 (66%) non-ectopic single adenomas in the nonlocalizing group and 325 (85%) single adenomas in the localizing group. There was no significant difference (p = 0.09) in adenoma quadrant between localizing and nonlocalizing single adenomas, but the most common location in both groups was right inferior. Patients with nonlocalizing scans were more likely to have double adenomas (21% vs. 9%, p < 0.001), ectopic glands (10% vs. 5%, p = 0.052), and multi-gland disease (13% vs. 8%, p = 0.002).

CONCLUSION

Nonlocalizing PHPT patients experienced similar cure and complication rates as localizing PHPT, but required more bilateral explorations and increased operative time.

Efficacy of surgeon-performed, intra-operative ultrasound scan for localisation of parathyroid adenomas in patients with primary hyperparathyroidism

BACKGROUND

In the UK, guidance recommends ultrasound scanning alone or in combination with sestamibi scintigraphy to guide surgery in patients with primary hyperparathyroidism. If an adenoma is localised on imaging, this can facilitate targeted or minimally invasive surgery. Surgeon-performed ultrasound scan on the operating table benefits from being performed on an anaesthetised patient with optimal positioning. The aim of this study was to investigate the efficacy of intra-operative, blinded, surgeon-performed ultrasound scan in localisation of parathyroid adenomas.

METHODS

Prospective data were collected on consecutive patients undergoing surgery for primary hyperparathyroidism at a single tertiary centre from November 2019 to June 2021. Patients underwent blinded, surgeon-performed ultrasound scan under general anaesthesia immediately prior to surgery. Localisation results from pre-operative imaging and surgeon-performed ultrasound scan were then compared with the intra-operative findings.

RESULTS

Forty-nine patients underwent surgery and were found to have single-gland disease. Sestamibi scintigraphy, radiologist-performed ultrasound scan and surgeon-performed ultrasound scan had sensitivities of 59.4, 43.75 and 73.8 per cent, respectively. Surgeon-performed ultrasound scan had a statistically significantly increased sensitivity compared with radiologist-performed ultrasound (p < 0.05).

CONCLUSION

Intra-operative, surgeon-performed ultrasound scan is effective in localising parathyroid adenomas and may be a useful adjunct to facilitate minimally invasive parathyroid surgery.

Association of Parathyroid and Differentiated Thyroid Carcinomas: A Narrative Up-To-Date Review of the Literature

Aim: Parathyroid carcinoma (PC) is a rare endocrine malignancy that represents 0.005% of all malignant tumors. Associated PC and differentiated thyroid carcinoma (DTC) is an exceptionally rare condition, and the preoperative diagnostics and proper treatment are challenging. Almost all PCs and the majority of DTCs are diagnosed postoperatively, making correct surgical treatment questionable. Specific guidelines for parathyroid and thyroid carcinomas association treatment are lacking. The purposes of our study were to identify the association between parathyroid and thyroid carcinomas, to analyze the available published data, and to evaluate the possible relationship between preoperative diagnostic and surgical decision-making, and outcome-related issues. Material and methods: We performed a literature review of several databases from the earliest records to March 2022, using controlled vocabulary and keywords to search for records on the topic of PC and WDTC pathological association. The reference lists from the initially identified articles were analyzed to obtain more references. Results: We identified 25 cases of PC and DTC association, 14 more than the latest review from 2021. The mean age of patients was 55, with a female to male ratio of about 3:1. Exposure to external radiation was identified in only one patient, although it is considered a risk factor the development of both PC and DTC. The preoperative suspicion of PC was stated by the authors in only 25% of cases, but suspicion based on clinical, laboratory, ultrasound (US), and fine needle aspiration (FNA) criteria could have been justified in more than 50% of them. With neck ultrasound, 40% of patients presented suspicious features both for PC and thyroid carcinoma. Intra-operatory descriptions of the lesions revealed the highest suspicion (83.3%) of PC, but en bloc resection was recommended and probably performed in only about 50% of the cases. Histopathological examinations of the thyroid revealed different forms of papillary thyroid carcinoma (PTC) in most cases. Postoperative normocalcemia was achieved in 72% of patients, but follow-up data was missing in about 25% of cases. Conclusion: Associated PC and DTC is an exceptionally rare condition, and the preoperative diagnostic and treatment of the patients is a challenge. However, in most cases pre- and intraoperative suspicious features are present for identification by a highly specialized multidisciplinary endocrine team, who can thus perform the optimal treatment to achieve curability.

Multiglandular Parathyroid Disease

Introduction: Multiglandular parathyroid disease (MGD) is an uncommon cause of primary hyperparathyroidism (pHPT) and has been reported in the literature in 8–33% of patients with pHPT. The aim of our study was to review the clinical characteristics and management of MGD and evaluation of surgical treatment failures. Methods: We performed a retrospective study of 163 patients with pHPT undergoing parathyroidectomy (PTX) at the Department of General and Endocrine Surgery between 1983 and 2018. All these patients were diagnosed with MGD. This group of patients was compared with a group of 856 patients with solitary disease operated for pHPT in the same period. Results: Among 163 patients—127 (79%) of them had two lesions, 28 (16%) had three, and 8 (5%) four. They were prevalently women over the age of 50. The diagnosis was based on PTH and ionized calcium studies and used sestamibi technetium-99m scintigraphy (MIBI) as well for us. Treatment was surgical. Conclusions: Parathyroidectomy (PTX) for multiglandular parathyroid disease (MGD) is associated with a higher operative risk of failure compared to solitary disease. Preoperative diagnosis and localization of the parathyroid glands is an extremely important element of treatment. Diagnosis is based on PTH and calcium levels. Ultrasonography (USG), MRI, and scintigraphy are very helpful in diagnosis. Mediastinal multiglandular parathyroid disease (MGD) is associated with increased surgical treatment failures. The treatment is surgical and consists of the removal of the masses or complete parathyroidectomy. Based on this study, we support the existence of multiple adenomas and advocate the removal of only macroscopically enlarged parathyroid glands in patients with primary hyperparathyroidism.

Surgeon-performed Ultrasound for Primary Hyperparathyroidism

The role of preoperative parathyroid imaging continues to evolve. This study evaluated whether surgeon-performed ultrasound (U/S) obviates the need for other imaging studies and leads to a focused exploration with a high degree of surgical success. From July 2010 to February 2012, 200 patients presenting with nonfamilial primary hyperparathyroidism underwent neck U/S in the surgeon's office. The U/S interpretation was classified as Class 1 if an adenoma was identified with high confidence, Class 2 if a possible but not definite enlarged gland was imaged, and Class 0 (zero) if no adenoma was identified. The findings were correlated with subsequent intra-operative findings. There were 144 Class 1 U/Ss (72%); of 132 patients coming to surgery, 96.2 per cent had surgical findings concordant with preoperative U/S and all had apparent surgical cure. Twenty-nine patients (14.5%) had Class 2 U/S; the 31 per cent confirmed false-positives in this group were usually colloid nodules. Fourteen of 27 with Class 0 U/S underwent surgery after being offered dynamically enhanced computed tomography scan. All 200 patients were apparent surgical cures. Surgeon-performed U/S is expedient, convenient, inexpensive, and accurate. A clearly identified adenoma can safely lead to a focused limited exploration and avoid additional imaging 93 per cent of the time.

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.

Current and future treatments for parathyroid carcinoma

Parathyroid carcinoma (PC) is a rare disease and presents clinical challenges in diagnosis, management and adjuvant treatment. Rarely diagnosed preoperatively, PC is often discovered in the treatment of primary hyperparathyroidism. PC is predominantly treated surgically with minimal additional treatments available. Given the rarity of the disease, current and future efforts, as discussed in this article, are focused on increasing preoperative diagnosis, recognizing genetic patterns and pathologic markers and delineating nonsurgical options for patients with advanced disease.

Sporadic multiple parathyroid gland disease--a consensus report of the European Society of Endocrine Surgeons (ESES)

BACKGROUND

Sporadic multiglandular disease (MGD) has been reported in literature in 8-33 % of patients with primary hyperparathyroidism (pHPT). This paper aimed to review controversies in the pathogenesis and management of sporadic MGD.

METHODS

A literature search and review was made to evaluate the level of evidence concerning diagnosis and management of sporadic MGD according to criteria proposed by Sackett, with recommendation grading by Heinrich et al. and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled 'Hyperparathyroidism due to multiple gland disease: An evidence-based perspective'.

RESULTS

Literature reports no prospective randomised studies; thus, a relatively low level of evidence was achieved. Appropriate surgical therapy of sporadic MGD should consist of a bilateral approach in most patients. Unilateral neck exploration guided by preoperative imaging should be reserved for selected patients, performed by an experienced endocrine surgeon and monitored by intraoperative parathormone assay (levels of evidence III-V, grade C recommendation). There is conflicting or equally weighted levels IV-V evidence supporting that cure rates can be similar or worse for sporadic MGD than for single adenomas (no recommendation). Best outcomes can be expected if surgery is performed by an experienced parathyroid surgeon working in a high-volume centre (grade C recommendation). Levels IV-V evidence supports that recurrent/persistence pHPT occurs more frequently in patients with double adenomas hence in situations where a double adenoma has been identified, the surgeon should have a high index of suspicion during surgery and postoperatively for the possibility of a four-gland disease (grade C recommendation).

CONCLUSIONS

Identifying preoperatively patients at risk for MGD remains challenging, intraoperative decisions are important for achieving acceptable cure rates and long-term follow-up is mandatory in such patients.

Ultrasonography alone can reliably locate parathyroid tumours and facilitates minimally invasive parathyroidectomy

INTRODUCTION

Minimally invasive parathyroidectomy (MIP) is performed via a short incision (≤3cm). Previous studies have employed multiple imaging modalities including ultrasonography, sestamibi imaging and/or intraoperative parathyroid hormone assay. We present our eight-year experience of MIP using ultrasonography alone.

METHODS

One hundred parathyroidectomies performed by a single surgeon between April 2004 and December 2012 were identified in a prospectively maintained database. All patients underwent ultrasonography including preoperative marking of the lesion by a single radiologist. No other localising diagnostic tests were performed.

RESULTS

Of the 100 patients (69% female) who underwent parathyroidectomy, 93 had MIP. The median age of all cases was 58 years (range: 19-90 years). All patients exhibited an elevated parathyroid hormone level (median: 19pmol) in the presence of hypercalcaemia (median: 2.86mmol/l, range: 2.54-3.94mmol/l). Conventional surgery was indicated in seven patients owing to the need for concurrent thyroidectomy. The median operative time was 30 minutes (range: 10-130 minutes). Ultrasonography localised parathyroid tumour position correctly in 98% of patients who underwent MIP, and in 97% across both MIP and non-MIP groups. Postoperative complications requiring treatment included pancreatitis and symptomatic hypocalcaemia. Follow-up review at 6-8 weeks demonstrated that 86% of open cases (6/7) and 94% of MIP cases (87/93) were rendered normocalcaemic.

CONCLUSIONS

Our study is the first to demonstrate that the sole use of ultrasonography including preoperative marking can localise parathyroid tumours correctly in 98% of cases suitable for MIP.

Long-term effectiveness of localization studies and intraoperative parathormone monitoring in patients undergoing reoperative parathyroidectomy for persistent or recurrent hyperparathyroidism

BACKGROUND

Reoperative parathyroidectomy (RPTX) for persistent or recurrent hyperparathyroidism is associated with a high rate of operative failure. The long-term effectiveness of RPTX using localization studies and intraoperative parathormone monitoring (IPM) was examined.

METHODS

Retrospective analysis of prospectively collected data from patients undergoing targeted RPTX with IPM for persistent or recurrent hyperparathyroidism was performed. Persistent hyperparathyroidism was defined as elevated calcium and parathormone (PTH) levels above normal range less than 6 months after parathyroidectomy. Recurrent hyperparathyroidism was defined as elevated calcium and PTH levels greater than 6 months after successful parathyroidectomy. Sensitivity and positive predictive value (PPV) for sestamibi, surgeon-performed ultrasound, intraoperative PTH dynamics, and surgical outcomes were evaluated.

RESULTS

Of the 1,064 patients, 69 patients underwent 72 RPTXs with localizing studies and IPM. Sestamibi (n = 69) had a sensitivity of 74% and a PPV of 83%, whereas surgeon-performed ultrasound (n = 38) had a sensitivity of 55% and a PPV of 76%. IPM had a sensitivity of 100% and a PPV of 98%. An intraoperative PTH drop greater than or equal to 50% was predictive of operative success (P < .01). Overall, operative success and recurrence were 94% and 1.4%, with a mean patient follow-up of 59 ± 12.8 months.

CONCLUSION

RPTX can be performed in a targeted approach using preoperative localization studies and IPM, leading to a low rate of complications and a high rate of long-term operative success.

Otolaryngologist-performed head and neck ultrasound: outcomes and challenges in learning the technique

Objective:

To assess the feasibility and accuracy of otolaryngologist-performed ultrasound in evaluating head and neck pathology.

Method:

An ENT trainee, who had undergone basic training in neck ultrasonography, performed this on patients referred with suspected neck pathology. The trainee recorded the presence and nature of any abnormality. Findings were compared with those from a repeated scan performed by an experienced head and neck radiologist.

Results:

The study included 250 patients. The absence or presence of lesion as reported by the trainee correlated with the radiologist's findings in 207 cases (83 per cent). There were 144 true positives, 63 true negatives, 32 false negatives and 11 false positives, yielding a sensitivity of 82 per cent, specificity of 85 per cent and accuracy of 83 per cent. Of the 144 true positive lesions, 81 per cent were interpreted concordantly with the radiologist.

Conclusion:

Neck ultrasonography performed by an otolaryngologist is less accurate than that performed by an experienced radiologist, but is still a useful adjunct to clinical assessment, facilitating assessment in a ‘one-stop’ clinical setting.

Incremental value and clinical impact of neck sonography for primary hyperparathyroidism: a risk-adjusted analysis

BACKGROUND

Despite the different preoperative imaging modalities available for parathyroid adenoma localization, there is currently no uniform consensus on the most appropriate preoperative imaging algorithm that should be routinely followed prior to the surgical management of primary hyperparathyroidism (PHPT). We sought to determine the incremental value of adding neck ultrasonography to scintigraphy-based imaging tests.

METHODS

In a single institution, surgically naive patients with PHPT underwent the following localization studies before parathyroidectomy: 1) Tc-99m sestamibi imaging with single photon emission computed tomography/computed tomography (SPECT/CT) or Tc-99m sestamibi imaging with SPECT alone, or 2) ultrasonography in addition to those tests. We retrospectively collected data and performed a multivariate analysis comparing group I (single study) to group II (addition of ultrasonography) and risk of bilateral (BNE) compared with unilateral (UNE) neck exploration.

RESULTS

Our study included 208 patients. Group II had 0.45 times the odds of BNE versus UNE compared with group I (unadjusted odds ratio [OR] 0.45, 95% confidence interval [CI] 0.25-0.81, p = 0.008). When adjusting for patient age, sex, preoperative calcium level, use of intraoperative PTH monitoring, preoperative PTH level, adenoma size, and number of abnormal parathyroid glands, Group II had 0.48 times the odds of BNE versus UNE compared with group I (adjusted OR 0.48, 95% CI 0.23-1.03, p = 0.06). In a subgroup analysis, only the addition of ultrasonography to SPECT decreased the risk of undergoing BNE compared with SPECT alone (unadjusted OR 0.40, 95% CI 0.19-0.84, p = 0.015; adjusted OR 0.38, 95% CI 0.15-0.96, p = 0.043).

CONCLUSION

The addition of ultrasonography to SPECT, but not to SPECT/CT, has incremental value in decreasing the extent of surgery during parathyroidectomy, even after adjusting for multiple confounding factors.

Is minimally invasive parathyroid surgery an option for patients with gestational primary hyperparathyroidism?

Background

Gestational primary hyperparathyroidism is associated with serious maternal and neonatal complications, which require prompt surgical treatment. Minimally invasive parathyroidectomy reduces pain, improves cosmesis and may achieve cure rates comparable to traditional open bilateral neck exploration. We report the clinical course of a woman with newly diagnosed gestational primary hyperparathyroidism and discuss the decision making behind the choice of video-assisted minimally invasive parathyroidectomy, amongst the other minimally invasive parathyroidectomy techniques available.

Case presentation

A 38-years-old pregnant woman at 9 weeks of gestation, with severe hyperemesis and hypercalcaemia secondary to gestational primary hyperparathyroidism (ionised calcium 1.28 mmol/l) was referred for surgery. Ultrasound examination of her neck identified 2 suspicious parathyroid enlargements. In view of pregnancy, a radioisotope Sestamibi parathyroid scan was not performed. Bilateral four-gland exploration was therefore deemed necessary to guarantee cure. This was performed with video-assisted minimally invasive parathyroidectomy, which relies on a single 15 mm central incision with external retraction and endoscopic magnification, allowing bilateral neck exploration.

Surgery was performed at 23 weeks of gestation. Four glands were identified in orthotopic positions of which three had normal appearance. The fourth was a right superior parathyroid adenoma of 756 mg. Ionized calcium (1.12 mmol/l) and PTH (0.9 pmol/l) normalised postoperatively. Patient was discharged on the second postoperative day, needing no pain relief. Cosmetic result was excellent. Her pregnancy progressed normally and she delivered a healthy baby.

Conclusion

Video-assisted minimally invasive parathyroidectomy allows bilateral four-gland exploration, and is an optimal technique to treat gestational primary hyperparathyroidism. This procedure removes the need for radiation exposure, reduces pain, improves cosmesis and may achieve cure rates comparable to traditional open bilateral neck exploration.

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.

Utility of surgeon-performed ultrasound assessment of the lateral neck for metastatic papillary thyroid cancer

Ultrasound is the recommended staging modality for papillary thyroid cancer. Surgeons proficient in US assessment of the neck and experienced in the management of papillary thyroid cancer (PTC) appear uniquely qualified to assess the lateral cervical lymph nodes for metastatic disease. Of 310 patients treated for PTC between 2000 and 2008, 109 underwent surgeon-performed ultrasound (SUS) of the lateral neck preoperatively. Fine needle aspiration was performed on suspicious lateral lymph nodes. SUS findings were compared with FNA cytology and results of postoperative imaging studies. The sensitivity and negative predictive value of SUS were 88% and 97%, respectively. Four patients were found to have missed metastatic disease within 6 months. No patient underwent a nontherapeutic neck dissection. SUS combined with US-guided FNA of suspicious lymph nodes can accurately stage PTC to reliably direct surgical management.

Nonlocalizing imaging studies for hyperparathyroidism: where to explore first?

BACKGROUND

For patients with primary hyperparathyroidism (pHPT), imaging studies are obtained to facilitate minimally invasive parathyroidectomy. If imaging studies are nonlocalizing, it is not known if exploration should begin on a particular side or gland location.

STUDY DESIGN

A retrospective review of a prospective parathyroid database was performed. The cohort consists of pHPT patients who underwent initial parathyroidectomy between December 1999 and July 2010 and had all preoperative imaging studies reported as nonlocalizing (negative or indeterminate).

RESULTS

Of 880 patients, 151 (17%) had nonlocalizing imaging studies. Reasons for starting exploration on a particular side were identified in 78 (52%) patients and included concomitant thyroid pathology (53%), suspicion on surgeon re-review of imaging (38%), or earlier thyroidectomy (9%). Exploration began on the right in 52%, the left in 42%, and was unknown in 6%. The surgeon had suspicion on imaging in 30 patients and correctly started on the side of pathology in 19 (63%). Hyperfunctioning glands were in eutopic locations in 144 patients (95%) and 3 had intrathyroidal glands. In 111 patients (74%) with single gland disease, median adenoma weight was 320 mg (range 80 to 8,210 mg). There was no difference in adenoma laterality (p = 0.7) or location (p = 0.8). Intraoperative parathyroid hormone criteria were met in 145 (96%) patients and 149 are eucalcemic at last follow-up; 2 (0.7%) patients have persistent disease.

CONCLUSIONS

In pHPT patients with nonlocalizing imaging, hyperfunctioning glands are not more frequently located on a particular side or anatomic position. Eutopic location is common and intraoperative parathyroid hormone monitoring should be used to guide the extent of surgery.

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.