Long-term results of unilateral neck exploration for preoperatively localized nonfamilial parathyroid adenomas

PET Imaging for Prostate Cancer

The role of PET imaging with ¹¹C-choline and ¹⁸F-fluciclovine in evaluating patients with prostate cancer (PCa) has become more important over the years and has been incorporated into the NCCN guidelines. A new generation of PET radiotracers targeting the prostate-specific membrane antigen (PSMA) is widely used outside the United States to evaluate patients with primary PCa and PCa recurrence. PET imaging influences treatment planning and demonstrates a significantly higher disease detection rate than conventional imaging such as computed tomography and MR imaging. Early data indicate that using PET radiotracers such as ¹⁸F-fluciclovine and PSMA improves patient outcomes. 68-Ga-PSMA-11 and 18F-DCFPyL-PET/CT were recently approved by the US Food & Drug Administration (FDA) for clinical use. Other PSMA radiotracers, including fluorinated variants, will likely gain FDA approval in the not-too-distant future.

Minimally Invasive Parathyroidectomy Versus Bilateral Neck Exploration for Primary Hyperparathyroidism

Primary hyperparathyroidism is a disease that is caused by excess parathyroid hormone (PTH) secretion from 1 or more of the parathyroid glands. Surgery is the only cure. Traditional surgical management consists of a 4-gland cervical exploration. Development of imaging specific to identification of parathyroid glands and application of the rapid PTH assay to operative management have made more minimal exploration possible. There are distinct advantages and disadvantages of minimally invasive parathyroidectomy (MIP) and bilateral neck exploration (BNE). The advantages of MIP seem to outweigh those of BNE, and MIP has replaced BNE as the operation of choice by many surgeons.

Intraoperative parathyroid hormone assay improves outcomes of minimally invasive parathyroidectomy mainly in patients with a presumed solitary parathyroid adenoma and missing concordance of preoperative imaging

OBJECTIVE

Intraoperative parathyroid hormone assay (IOPTH) is often used during minimally invasive parathyroidectomy (MIP) for primary hyperparathyroidism (pHPT). However, several investigators have reported conflicting outcomes, throwing doubt on the real influence of this adjunct on surgical decision-making. The aim of this study was to determine the impact of routine use of IOPTH on the success rate of MIP as the primary outcome, and whether it value-added to surgical decision-making during the operations at our institution.

DESIGN

The results of MIP were determined on postoperative follow-up in 177 consecutive patients with pHPT and compared with the results of preoperative imaging, findings at surgery and the value-added accuracy of IOPTH in surgical decisions.

PATIENTS

All 177 patients had biochemically documented pHPT and all were referred for first-time surgery.

MEASUREMENTS

Group 1 patients (n = 62) underwent a unilateral neck exploration (UNE) without IOPTH, and group 2 patients (n = 115) underwent MIP (either video-assisted or open) with IOPTH. The primary outcome was the cure rate, whereas the secondary outcome was the value-adding of IOPTH to surgical decision-making during MIP.

RESULTS

Of the group 1 vs. 2 patients, 57/62 (91.9%) vs. 114/115 (99.1%) were cured (P = 0.01). Five (8.1%) of the group 1 patients were hypercalcaemic postoperatively, owing to an additional, overlooked, hyperfunctioning parathyroid gland, whereas among the 115 group 2 patients, 104 (90.4%) underwent resection of a single parathyroid adenoma, met the Miami criterion, and were cured. The remaining 11 (9.6%) patients did not have an adequate reduction in parathyroid hormone levels and underwent further neck exploration, with resection of additional hyperfunctioning parathyroids in nine of them. One group 2 patient was not cured. However, a decrease of less than 50% of intraoperative parathyroid hormone (iPTH) assay correctly identified the risk of persistent disease in that patient. Another patient in group 2 had a false-negative IOPTH result. The value-added accuracy of IOPTH (correct assay-based surgeon's decision of further neck exploration) was demonstrated in 3 of 78 group 2 patients with concordant results of both imaging studies vs. 7 of 37 group 2 patients with only one positive imaging study, or 3.8 vs. 18.9% of patients (P = 0.007).

CONCLUSIONS

Routine use of IOPTH significantly improves cure rates of MIP in comparison to open image-guided UNE without IOPTH. It is a valuable adjunct in surgical decision-making, allowing for intraoperative recognition and resection of additional hyperfunctioning parathyroid tissue missed by preoperative imaging studies. IOPTH offers substantial value-adding to surgical decision-making, particularly in patients with only one positive imaging study result, and significantly improves the success rate of MIP in these patients. However, in patients with concordant results of two imaging studies, the assay offers significantly lower value-adding to surgical decisions, as a vast majority of patients are cured after removal of a two-image-indexed parathyroid lesion. Despite this, we strongly advocate routine use of IOPTH in all patients undergoing MIP, as this adjunct offers maximum safety for the patient and confidence for the surgeon.

Nonequivalent Results of Tetrofosmin and Sestamibi Imaging of Parathyroid Tumors

OBJECTIVE

To report the case of a patient with a large parathyroid carcinoma missed by dual-phase technetium Tc 99m tetrofosmin (TETRO) parathyroid scanning.

METHODS

We present the clinical findings, laboratory results, imaging studies, and surgical pathology report in a man with parathyroid carcinoma and review the literature regarding the use of TETRO scintigraphy in patients with hyperparathyroidism.

RESULTS

In an 83-year-old man with hyperparathyroidism, severe hypercalcemia developed in the context of nephrolithiasis. An in-office ultrasonographic evaluation of the neck revealed a partially calcified mass (2.3 by 1.3 by 1.6 cm) at the inferoposterior border of the left thyroid lobe. Technetium Tc 99m sestamibi (MIBI) scanning was requested and reported as "negative." In fact, TETRO scanning had been substituted for MIBI scanning by the management of the nuclear medicine facility. Before neck exploration, performance of dual-phase MIBI parathyroid scintigraphy revealed radionuclide retention in the left lower neck area at 120 minutes, in the same site as the ultrasonographically visualized mass. A limited left inferior parathyroidectomy was performed, and intraoperative parathyroid hormone levels declined from 254 pg/mL to 28 pg/mL 10 minutes after near-complete resection of the mass. Pathology evaluation of the surgical specimen revealed a 2,000-mg parathyroid carcinoma.

CONCLUSION

Although both agents incorporate the same technetium Tc 99m radionuclide, TETRO and MIBI parathyroid scanning are not equivalent in the detection of parathyroid tumors with use of the dual-phase technique. We do not recommend substitution of TETRO for MIBI as a cost-control measure in the evaluation of hyperparathyroidism.

Randomized clinical trial comparing scan-directed unilateral versus bilateral cervical exploration for primary hyperparathyroidism due to solitary adenoma

Background

It was shown in a previous retrospective study that scan-directed unilateral cervical exploration for primary hyperparathyroidism (HPT) can be carried out without an increase in the incidence of persistent or recurrent hypercalcaemia. This randomized clinical trial was conducted to test the hypothesis that focused unilateral operation leaves the patient no more vulnerable to persistent HPT than standard bilateral neck exploration.

Methods

Patients with HPT routinely underwent preoperative dual-isotope subtraction scintigraphy in an attempt to localize the presumed solitary parathyroid adenoma. Individuals with a positive scan (one residual focus of activity following subtraction) were deemed suitable for focused unilateral cervical exploration. At operation, if a single tumour was identified at the site suggested by the scan, the patient was randomized to unilateral or bilateral neck exploration.

Results

Between April 1998 and December 2003, 190 patients underwent first-time cervical exploration for HPT. Of these, 100 qualified for randomization. Fifty-four patients were randomized to unilateral neck exploration and 46 to bilateral operation. All 100 patients were cured following operation, as assessed by return of the serum calcium level to normal. Two patients randomized to bilateral exploration were found to have an unsuspected additional enlarged parathyroid on the contralateral side.

Conclusion

Scan-directed unilateral cervical exploration for HPT does not significantly increase the incidence of persistent hypercalcaemia compared with standard bilateral operation.

[Open minimally invasive parathyroid and thyroid surgery]

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

Selective unilateral parathyroid exploration: an effective treatment for primary hyperparathyroidism

BACKGROUND

Unilateral neck exploration (UNE) is a well-recognized approach in the treatment of primary hyperparathyroidism (PHP). The objective of this study was to review the success of an approach involving UNE guided by preoperative sestamibi (SM) scanning.

METHODS

All data were gathered by retrospective chart review. All patients undergoing surgery for the treatment of primary hyperparathyroidism at a tertiary referral center over a 3-year period were included in the study cohort.

RESULTS

Fifty-two of 80 patients (65%) had an SM scan consistent with a solitary adenoma and were eligible for a UNE, with 57.5% (46/80) undergoing a UNE. Seventy-seven of 80 (96.3%) patients were normocalcemic after initial neck exploration. UNE was curative in 50 of 52 (96.2%) UNE eligible patients and required less operative time than bilateral neck exploration (mean, 60 versus 87 minutes).

CONCLUSION

Selective unilateral neck exploration, guided by preoperative SM scanning, is an effective surgical approach for the management of primary hyperparathyroidism.

Reelevation of parathyroid hormone level after parathyroidectomy in patients with primary hyperparathyroidism: importance of decreased renal parathyroid hormone sensitivity

BACKGROUND

We hypothesized that impaired peripheral sensitivity to parathyroid hormone (PTH) may play a role in reelevation of PTH after successful operation for primary hyperparathyroidism (pHPT).

METHODS

Factors affecting reelevation of PTH were determined in 90 patients who underwent parathyroidectomy for pHPT. PTH/nephrogenous cyclic adenosine monophosphate ratio, as an index of renal resistance to PTH, was examined in relation to factors shown to influence reelevation of PTH.

RESULTS

Serum PTH levels were elevated above the upper limit of normal in 23 patients (26%) at 1 week and in 39 patients (43%) at 1 month after parathyroidectomy. These 39 normocalcemic patients with elevated serum PTH at 1 month after parathyroidectomy had a higher preoperative serum level of PTH and lower serum phosphate and 25-hydroxyvitamin D (25OHD) concentrations than those with normal PTH (n = 59). Elevated PTH and low 25OHD were shown by multivariate analysis to be significant predictors of reelevation of PTH. Renal resistance to PTH was higher in patients with vitamin D deficiency or renal insufficiency than in patients with normal serum vitamin D concentrations or normal renal function, and it increased according to increases in levels of PTH.

CONCLUSIONS

The mechanism of PTH reelevation in patients with pHPT after successful parathyroidectomy appears to be renal resistance to PTH.

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.

Lateral minimal parathyroidectomy: safety and cosmetic benefits

BACKGROUND

Surgery has been the cornerstone of treatment for primary hyperparathyroidism for almost three decades. The recent application of state-of-the art imaging technologies to localize hyperfunctioning adenomas preoperatively has enabled surgeons to minimize the surgical procedure, reduce total operation time and improve cosmetic results without compromising the cure rate.

STUDY DESIGN

Twenty-one patients with a diagnosis of primary hyperparathyroidism were selected for treatment with the lateral minimal parathyroidectomy approach following preoperative imaging with ultrasonography, Tc-sestamibi scan, or both. All patients were followed during hospitalization and for three months after for calcium levels and cosmetic results.

RESULTS

The procedure was performed by the same surgical team for all 21 patients; under general anesthesia in 20 patients and under deep sedation in 1 patient at high surgical risk. In all cases, parathyroid adenoma was accurately localized by at least one of the imaging modalities before surgery: ultrasonography in 16 patients (76%), Tc-sestamibi scan in 15 (71%), and both in 10 (48%). Average total operative time for the lateral minimal invasive approach was 46 minutes (range 30-65 minutes). Blood calcium levels returned to normal in all patients, and cosmetic results were graded good to excellent.

CONCLUSIONS

With accurate preoperative localization of unilateral parathyroid adenoma by any imaging modality and careful patient selection, lateral minimal parathyroidectomy performed by a skilled surgeon may serve as a safe, effective procedure with good clinical and aesthetic outcomes.

Unilateral neck exploration for primary hyperparathyroidism

Focused unilateral cervical exploration is a controversial alternative to conventional bilateral neck exploration for primary hyperparathyroidism (HPT) due to solitary adenoma. Development of preoperative localization techniques, notably isotope scintigraphy and small-part, real-time ultrasonography, has increased preoperative parathyroid tumor identification. Critics of scan directed unilateral neck exploration argue it may overlook enlarged parathyroid glands on the unexplored side, increasing the incidence of persistent and recurrent hypercalcemia. Our experience of this operation and prolonged follow-up of patients, however, confirm that it does not increase risk of persistent or recurrent HPT if a strict selection protocol is observed. This ensures the confident further development of minimally invasive surgical procedures for HPT based on the principle of a focused exploration following preoperative localization of the parathyroid adenoma.

Direct mini-incision parathyroidectomy

We describe our technique for performing a mini-incision parathyroidectomy in patients with hyperparathyroidism. Since our procedure differs from conventional parathyroidectomy in requiring a 2- or 3-cm skin incision and no raising of skin flap, this technique resulted in a good cosmetic status and less invasiveness. Hypesthesia or paresthesia in the neck and discomfort while swallowing related to a large skin incision and raising of skin flap are minimized. Although the cosmetic results of endoscopic techniques are better than those of our procedures, endoscopic instruments remain traumatic, can easily inflict iatrogenic lesions to parathyroid adenomas and enhance the risk of tumor cell exfoliation, especially if the parathyroid adenoma is manipulated by the instruments. Our surgical procedure can be less technically demanding and time-consuming. Although the number of patients whom we have treated in this manner is still small, we believe that our new procedure constitutes a useful surgical treatment for hyperparathyroidism.

Efficiency of gamma probe and dual-phase Tc-99m sestamibi scintigraphy in surgery for patients with primary hyperparathyroidism

PURPOSE

The purpose of this study was to determine the value of the intraoperative gamma probe and the efficacy of dual-phase Tc-99m sestamibi imaging in patients with primary hyperparathyroidism.

METHODS

Twenty-one patients with primary hyperparathyroidism were examined prospectively. Results of same-day dual-phase Tc-99m sestamibi scintigraphy and intraoperative gamma probe evaluations were compared with the intraoperative findings and histopathologic diagnoses. A 15-mm handheld gamma probe was used to measure gamma activity in the neck and upper mediastinum. Nuclear mapping by gamma probe showed a single quadrant of neck that emitted gamma radiation significantly greater than the other three quadrants, which correlated with the sestamibi scan.

RESULTS

Dual-phase Tc-99m sestamibi scintigraphy determined and localized parathyroid lesions in 20 patients (sensitivity, 94%). Of the 20 parathyroid lesions removed, 15 were located in normal positions, whereas five were explored in ectopic sites (one within the thyroid, one in the anterior mediastinum, one in a retrotracheal position, one in the carotid sheath, and one in the retroesophageal region). Although the index of thyroid nodules varied from 15.8% to 22.9%, the index for parathyroid lesions was 77.3% to 112.8%.

CONCLUSIONS

These results confirm that parathyroid lesions, especially at ectopic sites, can be treated successfully in shorter operative times with minimal complications with the help of the intraoperative gamma probe.

Minimally invasive, radioguided surgery for primary hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism affects 1 in 700 individuals in the United States. A single adenoma is responsible in over 85% of cases. Surgery remains the most effective treatment. This study was designed to assess the feasibility of minimally invasive radioguided parathyroidectomy (MIRP) with confirmation of excision by ex vivo radioactivity alone.

METHODS

Seventy-five consecutive patients with primary hyperparathyroidism were prospectively studied. Following sestamibi scan, patients underwent unilateral neck exploration guided by a handheld gamma probe, which was also used to measure ex vivo radioactivity of excised tissue.

RESULTS

The sestamibi scan was positive in 88% of the patients. A small incision (mean, 3.2+/-0.3 cm) was sufficient. Ectopic gland sites were localized in five patients with positive scans and single adenomas. Mean operative time was 48 minutes (range, 15-125 minutes), with shorter procedures after the initial 20 cases (mean, 24 vs. 72 minutes; P < .01). Radioguided parathyroidectomy was successful in 97%, with a mean follow-up of 11 months (range, 1-26 months). As noted previously, adenomatous parathyroid glands contained more than 20% of the background radioactivity.

CONCLUSIONS

MIRP is a feasible alternative to bilateral dissection with the advantages of guided dissection and rapid confirmation, and may become the procedure of choice for primary hyperparathyroidism.

Sestamibi scan-directed unilateral neck exploration for primary hyperparathyroidism due to a solitary adenoma

AIM

To evaluate the accuracy of Tc-99m sestamibi scintography in pre-operative localization of a single parathyroid adenoma and to determine if neck exploration can be limited to the side of the adenoma.

METHODS

Over a period of 4 years, 30 patients with primary hyperparathyroid disease underwent surgical treatment in the form of unilateral neck exploration after localization by Tc-99m sestamibi scintigraphy. The scan findings were interpreted by one radiologist with a special interest in parathyroid imaging and the operative findings were correlated with scan findings.

RESULTS

Tc-99 sestamibi scan localized a single parathyroid adenoma in 29 patients. There was doubtful uptake of isotope in one patient. Unilateral cervical exploration confirmed isotope scan findings in 29 patients with a positive scan, and these were subsequently proven by histology. In the patient with doubtful sestamibi scan, bilateral neck exploration was undertaken and three enlarged glands were excised. All the three glands were reported to be abnormal, consistent with either adenomas or hyperplasia. All the patients were normocalcaemic after 6 months follow-up.

CONCLUSIONS

Our results demonstrate that Tc-99m sestamibi scintigraphy is highly accurate in pre-operative localization of a single parathyroid adenoma when performed by an experienced radiologist. Unilateral cervical exploration, as directed by a positive Tc-99m sestamibi scintigram, seems to be a logical approach for the patients with primary hyperparathyroid disease due to solitary adenoma.

Minimally invasive parathyroid surgery

More surgeons are performing unilateral exploration for primary hyperparathyroidism (HPT) than ever before. This article reviews the factors that have led to the trend toward less invasive surgery. Discussion includes the history of unilateral exploration for HPT, the advent of magnetic resonance sestamibi imaging, and the development of intraoperative assays for parathyroid hormone. Results of minimally invasive techniques, including radio-guided parathyroidectomy, endoscopic parathyroidectomy, and outpatient parathyroidectomy, also are presented.

The utility of sestamibi scanning in the operative management of patients with primary hyperparathyroidism

BACKGROUND

The role of imaging studies before parathyroidectomy has been extensively debated and recent advances in unilateral parathyroidectomy intensify this controversy. The purpose of this study was to review the parathyroidectomy experience of a single surgeon, looking at the role of sestamibi scans and a standard postoperative care regimen.

STUDY DESIGN

Retrospective review of office and hospital charts was completed on 90 patients with primary hyperparathyroidism who underwent parathyroidectomy from 1991 to 1998. Patient workup and outcomes were noted, as were results of preoperative imaging. True-positive scans visualized an abnormality ipsilateral to the adenoma found at operation. Statistics were performed using nonparametric testing and Student's t-test.

RESULTS

There were 21 male and 69 female patients, with an average age of 54 years (range 29 to 81). There were zero mortalities, three morbidities (3.3%), and three patients who had persistent hypercalcemia, yielding a 96.7% success rate. Sixty-seven patients underwent preoperative sestamibi scanning, with a sensitivity of 74% and positive predictive value of 89%. Operative time in imaged patients averaged 103 +/- 49.9 minutes versus 121.5 +/- 85.9 minutes for patients without sestamibi scans. Operating time differences were not statistically significant and a preoperative sestamibi scan did not affect the success of parathyroidectomy. Discharge on postoperative day 1 was accomplished in 80% of patients and 13% were discharged the next day. There was no morbidity from hypocalcemia.

CONCLUSIONS

A preoperative sestamibi scan does not improve efficacy or decrease operating time for primary hyperparathyroidism when bilateral neck exploration is performed. A postoperative care protocol including oral calcium and vitamin D supplementation allows the majority of patients to be discharged on postoperative day 1 with excellent results.

Unilateral neck exploration under local anesthesia: the approach of choice for asymptomatic primary hyperparathyroidism

BACKGROUND

Conventional parathyroidectomy involves a bilateral neck exploration with the patient under general anesthesia with a thorough search for all parathyroid tissue. The purpose of this study was to assess the efficacy and safety of unilateral neck exploration under local anesthesia in patients with asymptomatic primary hyperparathyroidism (first-degree hyperparathyroidism).

METHODS

Of 679 patients who underwent parathyroidectomy for first-degree hyperparathyroidism from July 1989 to June 1997, 230 asymptomatic patients underwent unilateral neck exploration under local anesthesia. Selection criteria for this approach included the successful identification of a solitary parathyroid adenoma on preoperative imaging, no thyroid disease, and no family history of multiple endocrine neoplasia. Intact parathyroid hormone levels were monitored during the operation.

RESULTS

Total serum calcium levels were normal in 220 patients (96%) 3 to 6 months after surgery. Ten patients (4%) experienced persistent hypercalcemia, 8 of whom had multiple gland disease and 2 of whom had false-positive imaging. Two of these patients underwent bilateral neck exploration under general anesthesia and were cured, although 8 patients remained asymptomatic and were followed up non-operatively. The mean operating time was 30 minutes (range, 12-65 minutes). There were two complications (0.87%) including one wound hematoma and one transient recurrent laryngeal nerve palsy.

CONCLUSIONS

Unilateral neck exploration under local anesthesia is an efficacious and safe approach to the treatment of first-degree hyperparathyroidism and should be considered in all patients with asymptomatic disease.

Pre-operative localization and tissue uptake study in parathyroid imaging with technetium-99m-sestamibi

BACKGROUND

The diagnostic ability of 99mTc-sestamibi was compared with other techniques and the mechanism of parathyroid uptake was investigated.

METHODS

Double-phase 99mTc-sestamibi scanning was performed in 52 primary and 28 renal hyperparathyroidism patients. Gene expressions of mdr1 and mrp were examined by reverse transcriptase polymerase chain reaction in parathyroid tissue.

RESULTS

The sensitivity of 99Tc-sestamibi in primary and renal hyperparathyroidism was 91% and 75%, respectively, higher than for ultrasonography, T1/Tc subtraction scintigraphy, or computed tomography. Early 99mTc-sestamibi uptake was washed out in delayed images in 7% and 30% of glands in primary and renal hyperparathyroidism, respectively. Expression of mdr1 and mrp mRNA was found in 5 of 23 and 16 of 31 glands, respectively, and their expression correlated with washout in delayed images.

CONCLUSION

99mTc-sestamibi was the best localization test. mdr1 and mrp were associated with 99Tc-sestamibi washout, but their role in the parathyroid remains unclear.

Intrinsic limitations to unilateral parathyroid exploration

OBJECTIVE

To evaluate a method of limited parathyroid exploration for primary hyperparathyroidism.

SUMMARY BACKGROUND DATA

Although preoperative localization of parathyroid adenomas has become sensitive enough for clinical practice, it has not achieved success as the basis for limited parathyroid exploration, because multiglandular disease is routinely underdiagnosed. The rapid intraoperative parathyroid hormone assay is sensitive for multiglandular disease, because hormone levels will not fall within 10 minutes of adenoma removal if additional abnormal tissue is present. A combination technique in which the exploration is limited according to the localization studies and the success is confirmed with the parathyroid hormone assay has promise for producing a high rate of curative limited parathyroid explorations.

METHODS

Forty-eight consecutive patients with primary hyperparathyroidism and indications for surgery underwent preoperative localization. After tests, 45 patients underwent unilateral parathyroid exploration and confirmation of the success of unilateral exploration during surgery using the rapid parathyroid hormone assay. The intraoperative management of these patients and their follow-up to 3 months was recorded.

RESULTS

Thirty-two of the 48 patients (67%) had successful unilateral exploration as gauged by a marked drop in parathyroid hormone levels during the procedure and by 3-month clinical follow-up. Of the 16 patients who ultimately underwent bilateral exploration, 7 had parathyroid hormone levels that did not fall after adenoma removal. Of these seven, five were found to have a second adenoma and two had slow metabolism of hormone with no additional abnormal tissue found. In 5 of the 16 patients, bilateral exploration was performed for erroneous localization. Four additional patients underwent bilateral exploration for improved exposure or negative results on localization tests.

CONCLUSIONS

These results show that unilateral parathyroid exploration is limited by the intrinsic 15% rate of multiglandular primary hyperparathyroidism, combined with the imperfections of preoperative localizing techniques. Although an 85% rate of unilateral exploration can theoretically be obtained for unselected cases, the other vagaries of the technique make a 70% rate a more reasonable expectation.

Heterogeneous gland size in sporadic multiple gland parathyroid hyperplasia

BACKGROUND

The success rate for bilateral exploration in patients with primary hyperparathyroidism approaches 95%. Multiglandular parathyroid hyperplasia accounts for approximately 10% to 30% of primary hyperparathyroidism. The incidence of recurrent or persistent hyperparathyroidism is highest in familial forms of the disease, in which multiglandular disease is more common; this may be due to asymmetric enlargement of parathyroid glands. Because of improvements in tumor-imaging capability, some surgeons are now advocating unilateral exploration for primary hyperparathyroidism, but there is limited experience concerning how often these imaging methods fail.

STUDY DESIGN

The outcomes of 7 patients who had sporadic primary hyperparathyroidism with multigland hyperplasia were reviewed. We gathered demographic data and laboratory values and reviewed radiologic tests, surgical findings, pathologic findings, and postoperative followup.

RESULTS

All patients underwent preoperative localization with ultrasonography and technetium/sestamibi scans. The sensitivity of these two tests for the dominantly enlarged gland was 100% for both, but dropped to 0% and 5%, respectively, for all other enlarged glands. The sensitivity of CT and MRI for the dominant tumor was 67% (2 of 3) and 50% (1 of 2), respectively. Six of 7 patients underwent subtotal (3(1/2) gland) parathyroidectomy. The mean volume of all glands was 1.51+/-5.89 cm3 compared with a mean of 5.66+/-11.4 cm3 for all dominant glands and 0.123+/-0.1 cm3 for all nondominant hyperplastic glands. There was a large amount of variability between the volumes of dominant and other glands as demonstrated by large SDs from the mean.

CONCLUSIONS

There is a marked heterogeneity in gland size in patients with sporadic multigland hyperplasia, which is similar to that found in multiple endocrine neoplasia type I. This heterogeneity may result in failure to recognize multigland disease if a unilateral neck exploration is performed. Intraoperative parathyroid hormone assay may prove to be an important adjunct in this population of patients who have unsuspected multigland disease.

Secondary hyperparathyroidism is an expected consequence of parathyroidectomy for primary hyperparathyroidism: a prospective study

BACKGROUND

Parathyroidectomy for primary hyperparathyroidism (PHPT) can cause secondary hyperparathyroidism, with increased serum parathyroid hormone (PTH) and normal or low serum calcium concentrations.

METHODS

A prospective study investigated 78 consecutive patients who underwent exploration for PHPT. Serum intact PTH and total calcium concentrations were measured the evening after operation and ionized Ca++ the following morning. These levels were reassayed 1 week later.

RESULTS

Before operation, the mean PTH level was 138 +/- 15 pg/mL, total calcium concentration was 11.6 +/- 0.1 mg/dL, and ionized Ca++ concentration was 1.44 +/- 0.02 mmol/L. On the night of the operation, the PTH level was 11 +/- 2 pg/mL, and the total calcium concentration was 8.9 +/- 0.1 mg/dL. Fifty-five patients had hypoparathyroidism, with a PTH level less than 10 pg/mL. The day after the operation, the ionized Ca++ level was 1.14 +/- 0.01 mmol/L. One week later, PTH, ionized Ca++, and total serum calcium concentrations returned to normal levels. In 9 patients (12%), PTH levels were increased (98 +/- 16 pg/mL), although ionized Ca++ concentrations were normal (1.18 +/- 0.02 mmol/L), demonstrating secondary hyperparathyroidism. Risk factors for postoperative secondary hyperparathyroidism included older age, symptomatic hyperparathyroidism, higher preoperative PTH and alakaline phosphatase levels, and lower serum phosphorous levels. In 70% of these patients, PTH levels returned to normal in 3 to 12 months.

CONCLUSIONS

Secondary hyperparathyroidism occurs in 12% of patients after surgical treatment of PHPT. It is transient, possibly compensating for relative hypocalcemia.

99m-Technetium sestamibi localized solitary parathyroid adenoma as an indication for limited unilateral surgical exploration

BACKGROUND

Because of its successful localization of solitary adenomas, 99m-Technetium sestamibi (MIBI) may challenge the standard operation for primary hyperparathyroidism.

METHODS

Thirty-five consecutive patients underwent preoperative MIBI localization to optimize a surgical approach. Single-site localization in 21 patients directed a limited unilateral neck exploration (UNE) with adenomectomy and ipsilateral gland biopsy. Fourteen patients who did not localize underwent bilateral neck exploration (BNE). Conversion to a bilateral operation was required in 1 UNE patient because no adenoma was found on that side.

RESULTS

There were no significant differences in preoperative and postoperative serological markers between the two groups. However, the total operative time for UNE (49 +/- 21 minutes) was significantly less than for BNE (103 +/- 45 minutes; P <0.001).

CONCLUSIONS

Preoperative MIBI scan-directed limited unilateral neck operation may be used reliably for primary hyperparathyroidism due to a single adenoma, and thereby reduce operative time, extent of surgical dissection, and risk.

Minimally invasive parathyroidectomy facilitated by intraoperative nuclear mapping

BACKGROUND

The inability to predict the location and number of diseased parathyroid glands has precluded the wide acceptance of unilateral neck exploration for primary hyperparathyroidism. We used intraoperative nuclear mapping in patients identified by sestamibi scanning to have a single adenoma in hopes of minimizing operative intervention while maintaining the efficacy of a full exploration.

METHODS

Fifteen consecutive patients with primary hyperparathyroidism underwent technetium 99m-labeled sestamibi scanning 3.0 +/- 0.1 hours before operation. Placement of the initial 2.0 cm incision and all dissection were guided by quantitative gamma counting in four neck quadrants with an 11 mm Neoprobe. Ex vivo radioactivity was determined for parathyroid glands, fat, and lymph nodes. Potential radiation hazards were assessed.

RESULTS

Intraoperative nuclear mapping discriminated between 14 solitary adenomas and one patient with four-gland hyperplasia that was not predicted on preoperative sestamibi scanning. Removal of the adenoma resulted in a decline in radioactivity in that quadrant (p < 0.001) and the entire neck (p < 0.05), with equalization of all neck quadrants. Ex vivo counts always identified parathyroid tissue (p < 0.0001 versus fat and lymph node). Adenomas were located in 19 +/- 1.7 minutes through a 2.3 +/- 0.1 cm incision. No significant radiation hazard existed, and no special handling of the specimen was required (0.06 +/- 0.01 mR/hr).

CONCLUSIONS

Intraoperative nuclear mapping complements sestamibi scanning to help distinguish single-gland from multigland disease. This technique allows for a minimally invasive operation under local anesthesia in a true outpatient setting.

Minimally invasive videoscopic parathyroidectomy: a feasibility study in dogs and humans

BACKGROUND

With increasing experience using preoperative sestamibi nuclear scanning, several reports have shown that selective unilateral neck exploration is sufficient in most patients with primary hyperparathyroidism. The current study was undertaken to determine the feasibility of videoscopic parathyroidectomy as a means to decrease scar size while allowing adequate exposure for the identification of normal parathyroid glands and removal of those glands that are enlarged.

STUDY DESIGN

Eight mongrel dogs underwent removal of all parathyroid glands and both lobes of the thyroid using videoscopic techniques. Once the technical aspects of the operation were established, four patients with primary hyperparathyroidism underwent sestamibi-directed unilateral videoscopic neck exploration with attempted parathyroid removal.

RESULTS

All thyroid and parathyroid tissues were removed from each dog without complications. Maintenance of an adequate working space proved to be the major difficulty that necessitated placement of a small mechanical retractor. This problem was even more severe in humans, which prevented the identification of one of four adenomas and three of four normal glands.

CONCLUSIONS

Although videoscopic surgery is possible within the loose connective tissues of the canine neck, the inability to establish an adequate working space within the neck of humans and the location of parathyroid glands behind the thyroid precludes the use of this technique for patients with hyperparathyroidism.