Cost-effectiveness of preoperative sestamibi scan for primary hyperparathyroidism is dependent solely upon the surgeon's choice of operative procedure

Clinicopathological variables that correlate with sestamibi positivity in uniglandular parathyroid disease: a retrospective analysis of 378 parathyroid adenomas

PURPOSE

Technetium-99 m sestamibi parathyroid scintigraphy (MIBI scan) has been used to localize abnormal glands in patients with primary hyperparathyroidism to guide parathyroidectomy. This series aimed to identify the biochemical and histopathological correlates of MIBI scan findings in patients with parathyroid adenoma.

METHODS

A total of 378 patients with histologically and biochemically proven parathyroid adenoma were included. The results of MIBI scan, histopathological (gland volume and weight, oxyphil cell ratio), biochemical (blood and 24 h urine calcium, creatinine, glomerular filtration rate, parathormone, alkaline phosphate, and vitamin D3) variables were recorded. A positive uptake on the MIBI scan referred to a localized adenoma. Among histological variables, a cutoff of 30% was applied to define parathyroid adenomas with low (≤ 30%) and high (> 30%) oxyphil cell content. Statistical analyses were performed to assess the relationship among variables.

RESULTS

MIBI scan localized the adenoma in 306 patients. Parathyroid gland volume and weight, and oxyphil ratio were significantly higher in the MIBI scan-positive group. Among the biochemical variables, only PTH was found to be significantly increased in the MIBI scan-positive group. Binary logistic regression models identified statistically significant cutoffs for the gland volume (1700 mm3), gland weight (1.3 g) and PTH levels (170 pg/mL) that can be used to predict the MIBI scan positivity.

CONCLUSION

In addition to PTH levels, this series underscored the impact of cellular composition along with the parathyroid gland volume and weight, both of which correlate with sestamibi positivity in patients with benign uniglandular parathyroid disease.

Usefulness of 99mTc-SESTAMIBI Scintigraphy in Persistent Hyperparathyroidism after Kidney Transplant

Purpose

^99mTc-labeled sestamibi scintigraphy combined with single-photon emission computed tomography (SPECT) has a high positive predictive value for localizing hyperfunctioning parathyroid lesions in primary hyperparathyroidism (pHPT) but relatively low sensitivity and specificity in secondary hyperparathyroidism (sHPT) and tertiary hyperparathyroidism (tHPT). The purpose of this study is to investigate the usefulness of ^99mTc-sestamibi scintigraphy in persistent hyperparathyroidism after kidney transplant (KT).

Methods

Retrospectively evaluated 50 patients who received parathyroidectomy after KT at a single medical center. The parathyroid lesion with the highest sestamibi uptake intensity of a patient was graded from 0 to 3. Uptake intensity was analyzed in correlation with parathyroid hormone (PTH), calcium, ionized calcium, phosphorus, and vitamin D.

Results

Per-patient analysis, 43 patients had hyperplasia, 6 patients had adenomas, and 1 patient had a carcinoma. Only 3 patients with hyperplasia did not demonstrate any sestamibi uptake in the parathyroid scans. Out of the 148 pathologically confirmed parathyroid lesions, SPECT/CT images were able to identify 89 lesions (60%) and planar images of 71 lesions (48%). The average of sestamibi uptake intensity was mild at grade 1.6. Uptake intensity showed a positive correlation with parathyroid hormone (PTH) level but not with phosphorus, calcium, ionized calcium, or vitamin D levels. The largest lesion showed a high positive predictive value, especially in lesions with a diameter over 1.0 cm.

Conclusions

Regardless of relatively low and less discrete uptake in KT patients, it well depicts the largest and the most hyperfunctioning lesion.

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.

Minimally elevated preoperative parathyroid hormone level influences the management of primary hyperparathyroidism

OBJECTIVES/HYPOTHESIS

To determine the effect of preoperative parathyroid hormone (PTH) level on the extent of surgery and the accuracy of parathyroid imaging in primary hyperparathyroidism.

STUDY DESIGN

Retrospective cohort.

METHODS

Final diagnosis of single-gland adenoma and its location versus multigland disease was established in this retrospective cohort study. Positive predictive value, negative predictive value, and accuracy of imaging were analyzed in relation to preoperative PTH levels.

RESULTS

Eighty-seven percent of the 218 patients enrolled in the study underwent unilateral targeted operation and had a 97.9% (95% confidence interval: 95.8%-100%) success rate. However, in patients with PTH <65 pg/mL, 28.6% had bilateral exploration compared to 10.3% in those with PTH ≥65 pg/mL (P = .042). In patients with PTH <65 pg/mL, 7/21 (33.3%) had inaccurate sestamibi findings compared to 24/174 (13.8%) in patients with PTH ≥65 pg/mL (P = .047).

CONCLUSIONS

Accuracy of sestamibi drops significantly, by threefold, in patients with mild primary hyperparathyroidism and PTH <65 pg/mL. Patients with PTH < 65 pg/mL have a 2.5-fold higher rate of bilateral operation to identify the hypersecreting gland(s) compared to patients with PTH ≥65 pg/mL.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1016-1021, 2018.

Ultrastructure of Hyperfunctioning Parathyroid Glands: Does it Explain Various Patterns of 99mTc-sestamibi Uptake

The aim of this study was to correlate the uptake of ^99mTc-methoxy-isobutyl-isonitrile (MIBI) with ultra-structural features of parathyroid adenomas. Twenty patients with proven primary hyperparathyroidism were evaluated prospectively. Preoperative double-phase ^99mTc-MIBI scintigraphy was performed in all patients and the degree of tracer uptake by the parathyroid lesions was assessed visually and semi-quantitatively. The excised glands were examined histologically and ultrastructurally, and their features were correlated with the degree of the radiotracer uptake. At surgery, 21 parathyroid adenomas were removed (double adenoma in one patient and a solitary adenoma in each of the remaining 19 patients). ^99mTc-MIBI scan detected 18 of the 21 adenomas. There was positive correlation between the degree of ^99mTc-MIBI uptake and the mitochondrial contents of the parathyroid adenoma cells. Four adenomas with intense uptake had high content of mitochondria in the cells. The three false-negative scans had low-to-moderate mitochondrial content. ^99mTc-MIBI uptake is related to the mitochondrial content of the parathyroid adenoma cells.

4D MRI for the Localization of Parathyroid Adenoma: A Novel Method in Evolution

The sestamibi scan (MIBI) and ultrasound (US) are used for preoperative localization of parathyroid adenoma (PTA), with sensitivity as high as 90%. We developed 4-dimensional magnetic resonance imaging (4D MRI) as a novel tool for identifying PTAs. Eleven patients with PTA were enrolled. 4D MRI from the mandible to the aortic arch was used. Optimization of the timing of image acquisition was obtained by changing dynamic and static sequences. PTAs were identified in all except 1 patient. In 9 patients, there was a complete match between the 4D MRI and the US and MIBI, as well as with the operative finding. In 1 patient, the adenoma was correctly localized by 4D MRI, in contrast to the US and MIBI scan. The sensitivity of the 4D MRI was 90% and after optimization, 100%. Specificity was 100%. We concluded that 4D MRI is a reliable technique for identification of PTAs, although more studies are needed.

Focused parathyroidectomy without intra-operative parathyroid hormone monitoring for primary hyperparathyroidism: results in a low-volume hospital

BACKGROUND

The role of routine intra-operative parathyroid hormone monitoring for sporadic primary hyperparathyroidism is contentious. Satisfactory results can be achieved in high-volume centres. The results of low-volume hospitals are rarely studied.

METHODS

A retrospective, non-comparative study was conducted. From November 2002 to October 2012, 105 patients with clinically sporadic primary hyperparathyroidism underwent focused parathyroidectomy without intra-operative parathyroid hormone monitoring. Single adenoma was localised on pre-operative ultrasonography or sestamibi scan. The cure rate, surgical complication rate and pathology findings were evaluated.

RESULTS

Most of the operations (63.8 per cent) were performed under local anaesthesia. All but two patients (98.1 per cent) were cured after surgery. There was only one case of double adenomas. No recurrent hyperparathyroidism was observed after a mean follow up of 56.9 months. Surgical complications comprised two cases (1.9 per cent) of transient vocal fold palsy and one case (1.0 per cent) of permanent vocal fold palsy. Seven patients (6.7 per cent) suffered temporary hypocalcaemia.

CONCLUSION

Satisfactory results of focused parathyroidectomy without routine intra-operative parathyroid hormone monitoring for appropriately selected primary hyperparathyroidism cases can be attained in a low-volume hospital.

Minimally invasive parathyroidectomy without using intraoperative parathyroid hormone monitoring or gamma probe

OBJECTIVE

Minimal invasive parathyroidectomy (MIP) is a common surgical technique for the treatment of primary hyperparathyroidism (PHPT) and is usually done in conjunction with positive imaging techniques. We aimed to assess the results of this technique, performed without the use of intraoperative tests, in cases with PHPT caused by a single parathyroid adenoma.

MATERIAL AND METHODS

The data for patients who were diagnosed with PHPT were assessed retrospectively. Only those who had undergone a parathyroid adenoma localization study with ultrasonography (US) and parathyroid scintigraphy (PS) before the surgery, along with those patients for whom the MIP technique was routinely performed with frozen pathology, were included.

RESULTS

The study group was made up of 65 patients who had undergone the MIP technique. The mean age of the patients was 56±14 (20-81), with most being females [M/F: 19 (29.2%)/46 (70.8%)]. The mean calcium values before the operation were 11.24±1.26 mg/dL (8-15.5) (normal range: 8.4-10.2), and the parathyroid hormone (PTH) values were 388 pg/mL (249-707.75). These same values, measured 24 hours after the operation, were determined as 9.04±1.04 mg/dL (6.8-13.9) and 27 pg/mL (6-86), respectively. The follow-up period for the patients was an average of 26.6±9.4 (3-76) months, and only 3 (4.6%) cases of persistent hyperparathyroidism were detected within this period.

CONCLUSION

Our success rate with MIP in PHPT cases was determined to be 95.4%; therefore, this technique may be applied with a high success rate without any assistance from intraoperative tests, such as rapid serum PTH (rPTH) assays or gamma probes, in the presence of localization results of PS and US.

Evaluation of conventional imaging techniques on preoperative localization in primary hyperparathyroidism

We aimed to evaluate the diagnostic and preoperative localization capacity of 99mTc methoxyisobutylnitrile (MIBI) parathyroid scintigraphy and ultrasonography (USG) in enlarged parathyroid glands in the primary hyperparathyroidism (pHPT) as well as the relationship between the success rate of these techniques and biochemical values. In this study, we retrospectively evaluated 39 patients with clinical and biological evidence of pHPT who referred to the university hospital for MIBI parathyroid scintigraphy. Patients were examined with USG and double-phase MIBI parathyroid scintigraphy for the detection of enlarged parathyroid glands. Preoperative serum intact parathyroid hormone (iPTH) levels, calcium (Ca), phosphate and alkaline phosphatase measurements were obtained. A total of 45 parathyroid lesions in 39 patients were reviewed. Thirty-four patients had a single adenoma and 5 patients with multi-gland disease had 11 abnormal parathyroid glands including three adenomas, whereas the remaining 8 glands showed hyperplasia. The overall sensitivities of MIBI parathyroid scintigraphy, USG and combined techniques were 85.3%, 72.5% and 90.4%, respectively; the positive predictive values (PPV) were 89.7%, 85.2% and 92.6%, respectively. The most successful approach for detection of enlarged parathyroid glands in hyperparathyroidism is the concurrent application of USG and MIBI parathyroid scintigraphy modalities. The concomitancy of thyroid diseases decreases the sensitivity of both MIBI parathyroid scintigraphy and USG in enlarged parathyroid glands.

Intraoperative scintigraphy using a large field-of-view portable gamma camera for primary hyperparathyroidism: initial experience

Background. We investigated a novel technique, intraoperative ^99 mTc-Sestamibi (MIBI) imaging (neck and excised specimen (ES)), using a large field-of-view portable gamma camera (LFOVGC), for expediting confirmation of MIBI-avid parathyroid adenoma removal. Methods. Twenty patients with MIBI-avid parathyroid adenomas were preoperatively administered MIBI and intraoperatively imaged prior to incision (neck) and immediately following resection (neck and/or ES). Preoperative and intraoperative serum parathyroid hormone monitoring (IOPTH) and pathology (path) were also performed. Results. MIBI neck activity was absent and specimen activity was present in 13/20 with imaging after initial ES removal. In the remaining 7/20 cases, residual neck activity and/or absent ES activity prompted excision of additional tissue, ultimately leading to complete hyperfunctioning tissue excision. Postexcision LFOVGC ES imaging confirmed parathyroid adenoma resection 100% when postresection imaging qualitatively had activity (ES) and/or no activity (neck). The mean ± SEM time saving using intraoperative LFOVGC data to confirm resection versus first IOPTH or path result would have been 22.0 ± 2 minutes (specimen imaging) and 26.0 ± 3 minutes (neck imaging). Conclusion. Utilization of a novel real-time intraoperative LFOVGC imaging approach can provide confirmation of MIBI-avid parathyroid adenoma removal appreciably faster than IOPTH and/or path and may provide a valuable adjunct to parathyroid surgery.

Endotracheal ectopic parathyroid adenoma mimicking asthma

Primary benign tumors of the trachea are uncommon. These tumors may cause tracheal occlusion and lead to a misdiagnosis of asthma. Ectopic parathyroid adenoma (EPA) can be seen anywhere between the mandibular angle and the mediastinum. The distal part of the trachea is a rare location for EPA, and EPA obstructing the endotracheal lumen has not been reported in the literature. We herein describe a 52-year-old female with a several-year history of asthma treatment who presented with progressive dyspnea. Computed tomography revealed a mass that was obstructing the tracheal lumen. Total mass excision was performed via endobronchial treatment, and pathologic examination revealed EPA.

Predictors of accuracy in preoperative parathyroid adenoma localization using ultrasound and Tc-99m-Sestamibi: a 4-quadrant analysis

PURPOSE

To compare the accuracy of preoperative parathyroid adenoma localization in patients with primary hyperparathyroidism (pHPT) due to a single adenoma using a detailed 4-quadrant analysis and to identify patient and tumor characteristics associated with accurate preoperative localization.

MATERIALS AND METHODS

Retrospective review of 203 patients who underwent parathyroidectomy for pHPT due to a single adenoma between 2008 and 2011. Results from preoperative ultrasound and Tc-99m-sestamibi were compared to operative findings to determine accuracy of localization studies. Associations between clinicopathologic features and accurate preoperative adenoma localization were evaluated.

RESULTS

Ultrasound was performed on 198 patients, sestamibi on 177 patients, and both on 172 patients. Accurate localization occurred significantly more often for ultrasound than sestamibi (63% vs. 41%, P<0.001). For ultrasound, accurate localization was found in patients with larger or heavier adenomas, those with adenomas located inferiorly, patients not having a reoperative procedure, and patients with higher post-operative serum calcium levels. For sestamibi, greater adenoma size or weight, adenomas located inferiorly, and patients with associated thyroid cancer on pathology were most predictive of accurate preoperative localization.

CONCLUSIONS

Our results provide evidence that ultrasound is more accurate in localizing parathyroid adenomas in patients with pHPT due to a single adenoma when compared to sestamibi scan using 4-quadrant location analysis and may be the preferred preoperative imaging modality in these patients. No significant preoperative patient factors were associated with accurate localization by ultrasound or sestamibi, but adenoma size, weight, and location in an inferior position were predictive of accurate preoperative localization.

A comparison of minimally invasive video-assisted parathyroidectomy and traditional parathyroidectomy for parathyroid adenoma

Background: Pre-operative imaging techniques for sporadic primary hyperparathyroidism (SPHPT) and intraoperative parathyroid hormone (ioPTH) have led to the wide spread use of minimally invasive surgical approaches.

Study Design: In our prospectively collected database, 157 subjects with SPHPT and a preoperative diagnosis of parathyroid adenoma were treated with parathyroidectomy between January 2003 and November 2011. Subjects in group A were enrolled between January 2003 to September 2006, and underwent traditional parathyroidectomy with intraoperative frozen section and bilateral neck exploration. Subjects in group B were enrolled between September 2006 to November 2011, and underwent minimally invasive video-assisted parathyroidectomy (MIVAP) with ioPTH. Operative times and post-operative pain levels were compared between groups. Subjects were followed for a minimum of 6 months post-operatively and recurrence rates and complication rates were measured between groups.

Results: 81 subjects were enrolled in group A, and 76 subjects were enrolled in group B. Pre-operative evaluation demonstrated that the groups were statistically similar. Significantly decreased operative times (28min vs. 62min) and post-operative pain levels were noted in group B. Recurrence rates were similar between group A (3.7%) and group B (2.6%).

Conclusions: MIVAP with ioPTH demonstrated significantly improved operative times and post-operative pain levels, while maintaining equivalent recurrence rates.

Epidemiology of primary hyperparathyroidism

Primary hyperparathyroidism is the third most common endocrine disorder. The epidemiology of this disorder is increasingly well understood, but significant limitations still exist in our understanding of the mortality, hospitalizations, incidence, prevalence, and costs associated with this condition. These limitations are due to the small number of population-based epidemiologic studies that have evaluated this condition. Further studies will be required to fully characterize the epidemiology of primary hyperparathyroidism.

Could the eZ-SCOPE AN gamma camera replace intraoperative measurement of iPTH for PHPT?

Intraoperative intact parathyroid hormone (iPTH) measurements have been proposed as an effective assay in surgery for primary hyperparathyroidism (PHPT). We have demonstrated the efficiency of the use of a hand-held gamma camera, eZ-SCOPE AN, with technetium-99m sestamibi (Tc-MIBI) scintigraphy for navigation surgery for PHPT. The aim of this preliminary study was to assess the possibility that the eZ-SCOPE AN can replace the measurement of intraoperative iPTH in surgery for PHPT. Sixteen consecutive patients with documented primary hyperparathyroidism underwent surgery using this compact camera. iPTH was routinely measured preoperatively and 10 minutes after the complete removal of adenoma. All patients had a well-defined parathyroid lesion identified on preoperative Tc-MIBI. The eZ-SCOPE revealed hyperfunctioning parathyroid glands in all cases. iPTH levels were decreased in all cases after the removal of adenomas. Our results suggest that this gamma camera is useful for confirming complete resection of endocrinologically active tissue in surgery for PHPT. In selective patients with scan-positive cases identified by preoperative Tc-MIBI, the eZ-SCOPE may replace the intraoperative iPTH assay in surgery for PHPT.

Superiority of minimally invasive parathyroidectomy

Because greater than 80% of spontaneous cases of primary hyperparathyroidism are caused by a single adenoma, BCE of the neck, which has long been the approach of choice, is being replaced. Focused parathyroidectomy has been made possible by advances in preoperative parathyroid localization and IOPTH monitoring, which allows confirmation of cure and confirmation of the absence of MGD without visualizing all 4 parathyroids. Several techniques for focused parathyroidectomy exist, but open MIP through an incision of 2 to 3 cm with surgeon-administered locoregional anesthesia seems to improve on the already high success rate and low morbidity associated withimproe on bilateral exploration. In addition, MIP is associated with numerous secondary benefits such as decreased hospital cost, improved patient satisfaction, decreased operative time, and same-day discharge. Bilateral exploration will remain the standard of care for most patients with multigland or syndromic disease. Most patients with sporadic PHPT are candidates for MIP.

Sestamibi imaging for primary hyperparathyroidism: the impact of surgeon interpretation and radiologist volume

BACKGROUND

Preoperative localization is the first step towards minimally invasive targeted parathyroidectomy. While there are data emphasizing that surgeon experience optimizes operative outcomes, the role of the radiologist's experience in successful preoperative imaging is unclear. We hypothesized that the accuracy of sestamibi scanning for primary hyperparathyroidism is dependent upon surgeon interpretation and radiologist volume.

METHODS

Between January 2000 to August 2009, 1,255 patients underwent parathyroidectomy for hyperparathyroidism at our institution. Of these, 763 had sestamibi scans for primary hyperparathyroidism. All scans were reviewed by surgeons and radiologists blinded, and were correlated with the operative findings and pathological reports. Radiologists were grouped into high volume (>50 cases/year, HV-RAD) or low volume (<50 cases/year, LV-RAD) based upon a database of >6,000 parathyroid cases reported by 89 regional hospitals.

RESULTS

Of the 763 patients, 77 % were female and the mean age was 60 years. Mean baseline calcium and parathyroid hormone levels were 11.2 ± 0.03 mg/dl and 133 ± 3.27 pg/ml, respectively. The sensitivity of the surgeon (93 %) was higher than both HV (83 %) and LV (72 %) radiologists. Importantly, the positive predictive values were similar: 96 % for surgeon, 93 % for HV-RAD, and 98 % for LV-RAD. As a result, out of 99 scans which were correctly read by the surgeon but not by radiologist, 84 were read as negative by radiologist, 11 on the wrong side of the neck, and 4 on the same side but the wrong gland.

CONCLUSIONS

Surgeon interpretation and radiologist volume increase the likelihood of successful preoperative sestamibi parathyroid localization for primary hyperparathyroidism. We recommend that imaging be reviewed by experienced parathyroid surgeons rather than relying on radiological interpretation alone.

Abandoning unilateral parathyroidectomy: why we reversed our position after 15,000 parathyroid operations

BACKGROUND

Our group championed the techniques and benefits of unilateral parathyroidectomy. As our experience has matured, it seems this limited operation might be appropriate only occasionally.

METHODS

A single surgical group's experience with 15,000 parathyroidectomies examined the ongoing differences between unilateral and bilateral techniques for 10-year failure/recurrence, multigland removal, operative times, and length of stay.

RESULTS

With limited experience, 100% of operations were bilateral, decreasing to 32% by the 500(th) operation (p < 0.001), and long-term failure rates increased to 6%. Failures were 11 times more likely for unilateral explorations (p < 0.001 vs bilateral), causing gradual increases in bilateral explorations to 97% at the 14,000(th) operation (p < 0.001). Ten-year cure rates are unchanged for bilateral operations, and unilateral operations show continued slow recurrence rates of 5% (p < 0.001). Removal of more than one gland occurred 16 times more frequently when 4 glands were analyzed (p < 0.001), increasing cure rates to the current 99.4% (p < 0.001). Of 1,060 reoperations performed for failure at another institution, intraoperative parathyroid hormone levels fell >50% in 22% of patients, yet a second adenoma was subsequently found. Operative times decreased with experience; bilateral operations taking only 5.9 minutes longer on average (22.3 vs 16.4 minutes; p < 0.001), which is 25 minutes less than unilateral at the 500(th) operation (p < 0.001). By the 1,000(th) operation, incision size (2.5 ± 0.2 cm), anesthesia, and hospital stay (1.6 hours) were identical for unilateral and bilateral procedures.

CONCLUSIONS

Regardless of surgical adjuncts (scanning, intraoperative parathyroid hormone), unilateral parathyroidectomy will carry a 1-year failure rate of 3% to 5% and a 10-year recurrence rate of 4% to 6%. Allowing rapid analysis of all 4 glands through the same 1-inch incision has caused us to all but abandon unilateral parathyroidectomy.

Rapid intraoperative parathyroid hormone assay in the surgical management of hyperparathyroidism

CONTEXT

Historically, successful surgical management of primary hyperparathyroidism has required bilateral exploration of the neck. By confirming complete removal of hypersecreting tissue, an intraoperative parathyroid hormone (IO-PTH) assay allows use of a more limited procedure.

OBJECTIVE

Our objective was to evaluate the utility of IO-PTH assay used in 32 parathyroid explorations versus conventional bilateral exploration used before the advent of IO-PTH assays.

METHODS

Minimally invasive parathyroidectomy (MIP) was used. Plasma samples were obtained at several intervals and were analyzed for IO-PTH by use of a rapid immunochemiluminescent assay (ICMA). Outcomes were assessed by univariate inferential testing, yielding one-tailed t-test results.

RESULTS

The study group had a mean plasma IO-PTH level decrease of 87% at ten minutes after excision. All 32 patients who underwent MIP using IO-PTH monitoring had successful surgery. At last postoperative follow-up examination, all 32 patients were normocalcemic. There were statistically significant decreases in duration of surgery, length of hospital stay, and surgery cost.

CONCLUSIONS

IO-PTH levels predicted the postoperative outcome for all patients studied, can provide valuable information to surgeons, and can decrease the duration of surgery and hospital stay.

Use of a Handheld, Semiconductor (Cadmium Zinc Telluride)-Based Gamma Camera in Navigation Surgery for Primary Hyperparathyroidism

The recent development of gamma-ray probes makes it possible to perform radioguided surgery for primary hyperparathyroidism (PHPT). There have only been a few reports, however, regarding the use of a handheld gamma camera to detect parathyroid adenoma intraoperatively. The aim of this preliminary study was to assess the efficiency of a semiconductor gamma camera (eZ-SCOPE AN) in navigation surgery for PHPT. The eZ-SCOPE is designed to be used as a handheld, regional diagnostic imaging device. Eleven consecutive patients with documented primary hyperparathyroidism underwent surgery using this compact camera. Scintigraphy images of the neck by eZ-SCOPE were acquired: 1) before skin incision; 2) after adenoma location; 3) after adenoma excision; and 4) ex vivo imaging of the specimen. In scan-positive cases by preoperative Tc-MIBI, the eZ-SCOPE revealed parathyroid adenoma in all cases (100%), whereas ultrasound and CT showed a single adenoma in 63.6 and 72.7 per cent of cases, respectively. Navigation surgery for PHPT using the eZ-SCOPE permitted intraoperative identification and removal of parathyroid adenoma in all cases. Scintigraphy images of the neck by eZ-SCOPE also revealed a single adenoma even before skin incision. Our results suggest that Tc-MIBI scintigraphy with the eZ-SCOPE is useful for navigation surgery for PHPT. The eZ-SCOPE is useful for skin marking and could be easily applied for minimally invasive radioguided parathyroidectomy in scan-positive cases.

Minimally invasive video-assisted parathyroidectomy is a safe procedure to treat primary hyperparathyroidism

INTRODUCTION

Cervical exploration to identify the four parathyroid glands was considered to be the gold standard for management of primary hyperparathyroidism. In recent years, advances in preoperative localizing techniques have led to the use of more targeted, minimally invasive procedures to remove parathyroid glands. We present our series of patients who underwent Minimally Invasive Video-Assisted Parathyroidectomy (MIVAP) procedures and our results in treating primary hyperparathyroidism.

METHODS

Patients who underwent video-assisted parathyroidectomy were identified from a prospectively maintained database. Clinico-pathological data including indications for surgery, complications, conversion to open procedure and success of surgery were obtained from clinical notes.

RESULTS

A total of 56 patients underwent MIVAP between 2002 and 2010 at a district general hospital setup. The clinical indication was diagnosed primary hyperparathyroidism. Preoperative localization was attempted in all patients by sestamibi and high resolution ultrasound scans. The median age of patients was 65 years (32-82) and the median operating time was 78 min (20-168). Conversion to open procedure was done in 8/56 (14%) cases. The reason for conversion was failed exploration in 5 patients, inability to retrieve a very large friable adenoma in one patient, lipo-adenoma in one patient and very small parathyroid adenoma in one patient. Postoperative complications happened in one patient (2%) who developed postoperative sepsis resulting in temporary recurrent laryngeal nerve (RLN) palsy. All but 5 patients became normo-calcaemic following surgery.

CONCLUSION

MIVAP is a safe and effective procedure for treating patients with primary hyperparathyroidism. It also allows classical 4 gland exploration, whenever necessary.

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.

Bilateral neck exploration in primary hyperparathyroidism--when is it selected and how is it performed?

BACKGROUND

Although most patients with primary hyperparathyroidism (PHPT) are ideal candidates for minimally invasive parathyroidectomy, some will have more than one enlarged gland and require bilateral neck exploration to achieve biochemical cure. We evaluated the clinical evidence for when to choose bilateral neck exploration for patients with PHPT.

METHODS

We searched PubMed for English-language studies published from 1996 to 2008. The level of clinical evidence was determined according to the criteria proposed by Sackett (Chest 95[2 Suppl]:2S, 1989), and the grade of recommendation was established according to the criteria proposed by Heinrich et al. (Ann Surg 243:154, 2006).

RESULTS

Level III-IV evidence shows that patients with multiple endocrine neoplasia (MEN) 1 and PHPT should have a bilateral neck exploration (grade C recommendation). Only level IV evidence indicates that patients with familial PHPT should do so (no recommendation). Although most patients with MEN 2A have single-gland disease, bilateral neck exploration is still indicated, because they will have either a therapeutic or prophylactic total thyroidectomy for medullary thyroid cancer. A history of head and neck irradiation is associated with PHPT, but the risk of multi-gland parathyroid disease is apparently no higher than in sporadic cases (level IV evidence, no recommendation). Previous or current lithium therapy confers a higher risk of multi-gland disease (25%-45%; level IV-V evidence), which may require bilateral neck exploration. Preoperative localizing studies reliably identify most patients with single-gland but not multi-gland disease (level II-IV evidence). Negative localizing studies confer an approximately 50% risk of multi-gland disease and indicate that bilateral neck exploration is necessary. If two localizing studies are concordant, few patients will require bilateral neck exploration (level IV, no recommendation).

CONCLUSIONS

No level I or II evidence reliably identifies preoperative clinical risk factors for determining which patients should have routine bilateral neck exploration for multi-gland disease or for intraoperative decision making to convert to bilateral neck exploration. Imaging studies are positive in most patients (level II). No randomized studies exist to determine when a bilateral neck exploration is indicated based on clinical risk factors or imaging studies that may suggest multi-gland disease.

Tc-99m sestamibi parathyroid imaging in a rare case of parathyroid lipoadenoma

Parathyroid lipoadenoma is an unusual cause of primary hyperparathyroidism. Only a few earlier reports have documented parathyroid imaging in diagnostic studies of parathyroid lipoadenoma. Our case was a 27-year-old man, who was originally diagnosed with primary hyperparathyroidism. He underwent a Tc-99m sestamibi dual-phase parathyroid imaging study, which revealed a right-inferior parathyroid hyperfunctional lesion. The first operation removed a lesion of 1.5 cm in diameter in the area, and parathyroid lipoadenoma was diagnosed by pathology. However, hypercalcemia persisted. One week later, a Tc-99m sestamibi whole-body scan and another dual-phase imagining were performed, which demonstrated a residual lesion in the inferior part of the right thyroid region, while no ectopic lesion was found. A second surgery was performed and pathological diagnosis was confirmed as parathyroid lipoadenoma again. Our case demonstrated that although hyperfunctional parathyroid lipoadenoma is rare, Tc-99m sestamibi parathyroid imaging is reliable in locating the lesion for surgical purposes. And Tc-99m sestamibi imaging is useful in reoperative and persistent hyperparathyroidism situations as well.

Impact of concomitant thyroid pathology on preoperative workup for primary hyperparathyroidism

Background

The former standard surgical treatment in patients with primary hyperparathyroidism (pHPT) has been bilateral cervical exploration. New localization techniques and the possibility of intraoperative measurement of intact parathormone (iPTH) permit a focused, minimally invasive parathyroidectomy (MIP). The introduction of MIP without complete neck exploration leads to the potential risk of missing thyroid pathology. The aim of the present study is to evaluate the value of MIP in respect to coexisting thyroid findings and their impact on preoperative workup for primary hyperparathyroidism.

Methods

This is a prospective study including 30 consecutive patients with pHPT (median age 65 years; 17 females, 13 males). In all patients preoperative localization was performed by ultrasonography and ^99mTc-MIBI scintigraphy-Intraoperative iPTH monitoring was routinely done.

Results

Ten patients (33%) had a concurrent thyroid finding requiring additional thyroid surgery, and two patients (7%) with negative localization results underwent bilateral neck exploration. Therefore, MIP was attempted in 18 (60%) patients. The conversion rate to a four gland exploration was 6% (1/18). The sensitivities of ^99mTc-MIBI scanning and ultrasonography were 83.3% and 76.6%, respectively. The respective accuracy rates were 83.3% and 76.6%. Of note, the combination of the two modalities did not improve the sensitivity and accuracy in our patient population. During a median follow-up of 40 months, none of the patients developed persistent or recurrent hypocalcaemia, resulting in a 100% cure rate.

Conclusion

Coexisting thyroid pathology is relatively frequent in patients with pHPT in our region. Among patients having pHPT without any thyroid pathology, the adenoma localization is correct with either ultrasonography or ^99mTc-MIBI scintigraphy in the majority of cases. MIP with iPTH monitoring are highly successful in this group of patients and this operative technique should be the method of choice.

Parathyroid lipoadenomas and lipohyperplasias: clinicopathologic correlations

Parathyroid lipoadenomas and lipohyperplasias are rare histologic variants with both an increase in stromal fat and parenchyma. We report the most comprehensive single institution series of lipoadenomas and lipohyperplasias to date and review the literature. Eight lipoadenomas and 3 lipohyperplasias (27 y period) were reviewed. The mean age was 60.3 years (range: 50 to 77 y) with a female predilection (1.75:1). The most common symptoms on presentation were fatigue (55.6%) and bone/joint pain (44.4%). Only 1 patient was euparathyroid. Ultrasound localized lipoadenomas in 50% of tested cases whereas sestamibi was successful in 71.4%. Despite increased stromal fat (median: 50%), the weight and the appearance of large, occasionally nodular expansions of parathyroid parenchyma within the fatty stroma distinguished lipoadenomas and lipohyperplasias from normal parathyroid tissue; none of the cases were misclassified as normal on frozen section. Mean weight for lipoadenomas was 1553 mg (range: 173 to 4587 mg), whereas the mean weight for lipohyperplasia glands was 389.1 mg. Variant morphologies included follicular patterned, oxyphil predominant, and thymic elements (thymolipoadenoma). In 1 lipohyperplasia case, not all glands were involved. Oil Red O stains showed decreased intracytoplasmic lipid in most cases. Median follow-up was 9.2 months (range: <1 to 51 mo). Only 1 lipohyperplasia patient had persistent hypercalcemia, but was asymptomatic. Lipoadenomas and lipohyperplasias are clinically similar and as histologically diverse as their conventional counterparts. Lipoadenomas are more difficult to localize preoperatively by imaging. Despite the potential difficulty at frozen section, accurate weight documentation and recognition of key histologic features diminish this challenge.

Focused approach to parathyroidectomy

Minimally invasive parathyroidectomy is performed after preoperative parathyroid localization-usually with high-quality sestamibi scans and/or ultrasonography-often under cervical block anesthesia during which a limited exploration is performed. The rapid intraoperative parathyroid hormone assay is then employed to confirm an adequate resection and cure of primary hyperparathyroidism. This article discusses imaging, anesthesia, results, and the surgical management of patients undergoing minimally invasive parathyroidectomy.

The cost-effectiveness of three strategies for the surgical treatment of symptomatic primary hyperparathyroidism

INTRODUCTION

Modern surgical approaches to the treatment of primary hyperparathyroidism [unilateral neck exploration (UNE) and minimally invasive parathyroidectomy (MIP)] have become commonplace in recent years. However, the cost-effectiveness of these strategies has been questioned since the effectiveness of the gold standard, bilateral neck exploration (BNE), is well established. The objective of our study was to determine the incremental cost effectiveness of UNE and MIP compared with BNE for treatment of primary hyperparathyroidism (HPT).

METHODS

Patients presenting to a tertiary endocrine surgical center for treatment of HPT over a 38-month period were included in the study. The primary measure of effectiveness was the rate of postoperative complications (hypocalcemia and paresthesias) observed in our cohort. A decision analytic model was constructed to determine the incremental cost-effectiveness ratios (ICERs) of the UNE and MIP strategies compared with the BNE strategy. Deterministic and probabilistic sensitivity analyses were conducted to evaluate uncertainty around model-based estimates of costs and effectiveness.

RESULTS

A total of 94 patients (56 BNEs, 19 UNEs, and 19 MIPs) provided estimates of mean costs (BNE = $4524, UNE = $4784, MIP = $4961) and success rates (BNE = 0.91, UNE = 0.86, MIP = 0.93) for each treatment arm. The gold standard BNE strategy dominated the UNE strategy (lower cost, higher effectiveness) under most model formulations. The MIP strategy had an ICER of $28,439 per complication avoided, which is likely to be above societal willingness to pay to avoid primarily minor postoperative complications.

CONCLUSION

Our results suggest that within our institution, and in several different model formulations, bilateral neck exploration remains the cost-effective strategy for the treatment of primary hyperparathyroidism.

Parathyroid exploration in the reoperative neck: improved preoperative localization with 4D-computed tomography

BACKGROUND

Reoperation for hyperparathyroidism (HPT) carries an increased risk for morbidity and failure to cure. Accurate preoperative localization minimizes operative risk but is often difficult to achieve in the reoperative setting. Four-dimensional computed tomography (4D-CT) is an emerging technique that uses functional parathyroid anatomy for precise preoperative localization. We evaluated 4D-CT as a tool for localization of hyperfunctioning parathyroid tissue in the reoperative setting.

STUDY DESIGN

A prospective endocrine database was queried to identify 45 patients who underwent reoperative parathyroidectomy after preoperative localization using 4D-CT. The patients were categorized into 1 of 3 groups: group 1 included those who had previous neck surgery for non-HPT conditions; group 2 included those who had undergone a previously unsuccessful neck exploration for HPT; and group 3 included patients with HPT who had a previous neck exploration with resection of at least 1 hypercellular parathyroid.

RESULTS

The sensitivity of 4D-CT for localization was 88% compared with 54% for sestamibi imaging. Four-dimensional CT more often correctly localized (p=0.0003) and lateralized (p=0.005) hyperfunctional parathyroid tissue than sestamibi did. Four-dimensional CT successfully localized hyperfunctional parathyroid tissue in 18 (82%) of 22 group 1 patients, 10 (91%) of 11 group 2 patients, and 8 (67%) of 12 group 3 patients. Three patients were lost to followup. At a mean followup of 9.8 months, 39 (93%) of 42 patients were surgically cured and 3 patients (7%; 2 in group 3) had persistent HPT.

CONCLUSIONS

Four-dimensional-CT is an ideal tool for preoperative localization of hyperfunctioning parathyroid tissue in the reoperative setting. Localization and successful reoperation are most difficult in patients who have undergone an earlier operation that included resection of at least one hypercellular parathyroid suggesting multigland disease.

Utility of an intraoperative gamma probe in the surgical management of secondary or tertiary hyperparathyroidism

BACKGROUND

In primary hyperparathyroidism the gamma probe is effective, but its role in secondary hyperparathyroidism is unclear. We investigated the utility of the probe in the surgical management of secondary and tertiary hyperparathyroidism.

METHODS

The value of the probe in guiding resection of parathyroids was determined prospectively in 29 patients with secondary or tertiary hyperparathyroidism. Resected tissues with radioactivity of greater than 20% as compared with the wound bed was considered hyperfunctional parathyroid and was confirmed histologically.

RESULTS

The probe was helpful in guiding resection in 13% of the hyperplastic glands, including ectopic glands and those not detected preoperatively. The gamma probe confirmed the presence of hyperfunctional parathyroid after resection with a sensitivity and specificity of 97% and 92%, respectively.

CONCLUSIONS

The probe is particularly useful in confirming the presence of hyperfunctional parathyroids after resection. It also is useful in identifying ectopic localizations, but its value is limited in guiding surgery for secondary or tertiary disease.

Surgeon-performed ultrasonography as an adjunct to minimally invasive radio-guided parathyroidectomy in 100 consecutive patients with primary hyperparathyroidism

OBJECTIVE

To examine whether surgeon-performed ultrasonography (SPU) in patients with primary hyperparathyroidism and negative preoperative sestamibi scans improves adenoma localization, increases the directed unilateral exploration rate, and reduces operative time and length of hospital stay.

METHODS

We retrospectively analyzed 100 consecutive patients with primary hyperparathyroidism encountered between January 1, 2005, and March 31, 2007. Patients underwent preoperative sestamibi scanning and SPU. Minimally invasive radio-guided parathyroidectomy (MIRP) was performed on patients with positive sestamibi scans. In sestamibi scan-negative patients, unilateral exploration was performed with removal of the adenoma, which was submitted for frozen section. Accuracy, operative time, hospital length of stay, mortality, and morbidity were assessed.

RESULTS

Of 100 patients, 79 had positive sestamibi scans and underwent MIRP. Twenty-one had negative sestamibi scans, 18 of whom underwent SPU. Parathyroid adenoma was localized in 17 (94%) of the 18 patients. Operative time and length of hospital stay were not significantly different between sestamibi scan-negative patients who underwent SPU with directed unilateral exploration and sestamibi scan-positive patients who underwent MIRP (operative time: 46 minutes vs 38 minutes, respectively; length of hospital stay: 17.8 hours vs 16.1 hours, respectively). Operative time and length of hospital stay were significantly shorter in sestamibi scan-negative patients who underwent SPU with directed unilateral exploration and in patients who underwent MIRP than in historical controls who underwent 4-gland exploration (P<.01 for both outcomes). No morbidity or mortality was documented.

CONCLUSION

SPU localizes 94% of adenomas in sestamibi scan-negative patients, which allows for directed unilateral exploration and results in operative time and length of hospital stay not significantly different from patients undergoing MIRP.

Phantom experiments to improve parathyroid lesion detection

This investigation tested the hypothesis that visual analysis of iteratively reconstructed tomograms by ordered subset expectation maximization (OSEM) provides the highest accuracy for localizing parathyroid lesions using 99mTc-sestamibi SPECT data. From an Institutional Review Board approved retrospective review of 531 patients evaluated for parathyroid localization, image characteristics were determined for 85 99mTc-sestamibi SPECT studies originally read as equivocal (EQ). Seventy-two plexiglas phantoms using cylindrical simulated lesions were acquired for a clinically realistic range of counts (mean simulated lesion counts of 75 +/- 50 counts/pixel) and target-to-background (T:B) ratios (range = 2.0 to 8.0) to determine an optimal filter for OSEM. Two experienced nuclear physicians graded simulated lesions, blinded to whether chambers contained radioactivity or plain water, and two observers used the same scale to read all phantom and clinical SPECT studies, blinded to pathology findings and clinical information. For phantom data and all clinical data, T : B analyses were not statistically different for OSEM versus FB, but visual readings were significantly more accurate than T : B (88 +/- 6% versus 68 +/- 6%, p = 0.001) for OSEM processing, and OSEM was significantly more accurate than FB for visual readings (88 +/- 6% versus 58 +/- 6%, p < 0.0001). These data suggest that visual analysis of iteratively reconstructed MIBI tomograms should be incorporated into imaging protocols performed to localize parathyroid lesions.

The positive effect of adenoma weight and oxyphil cell content on preoperative localization with 99mTc-sestamibi scanning for primary hyperparathyroidism

BACKGROUND

Although the sensitivity of sestamibi scanning (MIBI) is high in patients with solitary parathyroid adenomas, negative sestamibi scan results are inevitable. The exact mechanism of visualization of abnormal and hyperfunctioning parathyroid tissue is not yet clear. The aims of this clinical study were (1) to evaluate positive and negative sestamibi scan results with regard to adenoma weight and oxyphil cell content and (2) to compare the effects of adenoma weight and oxyphil cell content on the results of sestamibi scanning.

PATIENTS

The patients were divided in 2 groups according to their sestamibi scan results. Group 1 consisted of 27 patients with positive sestamibi scan results, and group 2 consisted of 20 patients with negative sestamibi scan results. Parathyroid adenoma weight and oxyphil cell content were determined in all patients.

RESULTS

The weight and oxyphil cell content of the parathyroid adenomas in the patients of group 1 were significantly higher than those in the patients of group 2 (P = .001). An adenoma weight >600 mg and an oxyphil cell content >20% increased the rate of obtaining a positive sestamibi scan result 10- and 4-fold, respectively.

CONCLUSIONS

Both adenoma weight and oxyphil cell content were found to significantly correlate with positive sestamibi scan results. In patients with high-weight adenomas, adenoma weight was the most significant factor in obtaining positive MIBI scan results, whereas in patients with low adenoma weights, high oxyphil cell content was the most significant factor in obtaining positive MIBI scan results.