Reoperation for suspected primary hyperparathyroidism

Parathyroid Adenoma Orientation for Gland Embryologic Origin on Ultrasonography

Importance

Accurate preoperative localization is critical to success in targeted parathyroidectomy for primary hyperparathyroidism.

Objective

To determine if the association between the long axis of a parathyroid adenoma (PTA) candidate and strap musculature on sagittal ultrasonography (US) can be used to predict the embryologic origin of the gland.

Design, Setting, and Participants

This diagnostic study was performed using the Stanford Research Repository. Patients 18 years or older with primary hyperparathyroidism who underwent parathyroidectomy between January 2009 and October 2021 were considered. Additional inclusion criteria were having clear sagittal view of the adenoma candidate on US, confirmation of the gland of origin intraoperatively, and confirmation of hypercellular parathyroid on final pathology. Data were analyzed from October 2021 to June 2022.

Exposures

B-mode US and surgical parathyroidectomy.

Main Outcomes and Measures

The index test was using US to measure the angle between the long axis of an adenoma candidate and the strap musculature in the sagittal plane. This angle was used to test whether inferior and superior PTAs could be accurately assigned. The hypothesis was formulated prior to data collection.

Results

A total of 426 patients (mean [range] age, 61.1 [20-96] years; 316 [74.2%] female) with 442 adenomas met inclusion criteria. Of the 442 adenomas, 314 (71.0%) had measurable angles, of which 204 (46.2%) were assigned a superior origin, 238 (53.8%) were assigned an inferior origin, and 128 (29%) were indeterminate. Of the surgically identified superior PTAs, 144 (70.6%) had a definable angle, and of the surgically identified inferior PTAs, 170 (71.4%) had a definable angle. The receiver operating characteristic analysis found 94° as the optimized angle for differentiating true negatives from true positives, with an overall sensitivity of 74% and specificity of 72%. This supported using 90° as a break point for US review. True positives were considered superior adenomas with an angle greater than 90°; true negatives were inferior adenomas with an angle less than 90°. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of angulation analysis for determining PTA origin were 72.2% (95% CI, 64.9%-79.5%), 73.5% (95% CI, 66.9%-80.1%), 69.8% (95% CI, 62.5%-77.1%), 75.8% (95% CI, 69.3%-82.3%), and 72.9%, respectively. A subgroup analysis of 426 adenomas using the posterior carotid artery border on transverse US as a surrogate for predicting gland origin showed the following for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy: 49.5% (95% CI, 42.6%-56.4%), 82.3% (95% CI, 77.3%-87.3%), 71.4% (95% CI, 63.9%-78.9%), 64.6% (95% CI, 59.1%-70.1%), and 66.9%, respectively.

Conclusions and Relevance

This diagnostic study showed that PTA angulation on sagittal plane US can be used to predict gland of origin and guide surgery. The relationship between adenoma and posterior carotid artery border on transverse US can also be used to predict gland origin. These easy-to-apply US-based tests can be used in conjunction with other imaging modalities to guide targeted parathyroidectomy.

Localization of Parathyroid Disease in Reoperative Patients with Primary Hyperparathyroidism

The localization of persistent or recurrent disease in reoperative patients with primary hyperparathyroidism presents challenges for radiologists and surgeons alike. In this article, we summarize the relevant imaging modalities, compare their accuracy in identifying reoperative disease, and outline their advantages and disadvantages. Accurate localization by preoperative imaging is a predictor of operative success, whereas negative or discordant preoperative imaging is a risk factor for operative failure. Ultrasound is a common first-line modality because it is inexpensive, accessible, and radiation-free. However, it is highly operator-dependent and less accurate in the reoperative setting than in the primary setting. Sestamibi scintigraphy is superior to ultrasound in localizing reoperative disease but requires radiation, prolonged imaging times, and reader experience for accurate interpretation. Like ultrasound, sestamibi scintigraphy is less accurate in the reoperative setting because reoperative patients can exhibit distorted anatomy, altered perfusion of remaining glands, and interference of radiotracer uptake. Meanwhile, four-dimensional computed tomography (4DCT) is superior to ultrasound and sestamibi scintigraphy in localizing reoperative disease but requires the use of radiation and intravenous contrast. Both 4DCT and magnetic resonance imaging (MRI) do not significantly differ in accuracy between unexplored and reoperative patients. However, MRI is more costly, inaccessible, and time-consuming than 4DCT and is inappropriate as a first-line modality. Hybrid imaging with positron emission tomography and computed tomography (PET/CT) may be a promising second-line modality in the reoperative setting, particularly when first-line modalities are discordant or inconclusive. Lastly, selective venous sampling should be reserved for challenging cases in which noninvasive modalities are negative or discordant. In the challenging population of reoperative patients with PHPT, a multimodality approach that utilizes the expertise of high-volume centers can accurately localize persistent or recurrent disease and enable curative parathyroidectomy.

Intraoperative Parathyroid Hormone Monitoring in Guiding Adequate Parathyroidectomy

BACKGROUND

Parathyroidectomy has been traditionally performed through bilateral neck exploration (BNE). However, with the use of intraoperative parathyroid hormone (IOPTH) assay along with preoperative localization studies, focused parathyroidectomy can be performed with good surgical success rate, multiglandular disease can be predicted, and hence recurrence and surgical failure can be prevented. Furthermore, it predicts eucalcemia in the postoperative period. The aim of this study was to evaluate the usefulness of IOPTH assay in guiding adequate parathyroidectomy in patients of primary hyperparathyroidism.

MATERIALS AND METHODS

Between year 2015 and 2017, 45 patients of primary hyperparathyroidism underwent parathyroidectomy with IOPTH assay employed as an intraoperative tool to guide the surgical procedure. Blood samples were collected: (1) at preincision time, (2) preexcision of gland, (3) 5-min postexcision of gland, and (4) 10-min postexcision of gland. On the basis of the Irvin criterion, an intraoperative PTH drop >50% from the highest either preincision or preexcision level after parathyroid excision was considered a surgical success. Otherwise, BNE was performed and search for other parathyroid glands done.

RESULTS

Ten-min postexcision PTH levels dropped >50% in 34 (75.6%) patients. True positive among them were 31 (68.8%), true negative 8 (17.7%), false positive 3 (6.6%), and false negative 3 (6.6%). We performed focused exploration at the outset in 40 (88.9%) patients and bilateral exploration for five patients as guided by preoperative localizing studies. Hence, IOPTH was helpful in guiding further exploration in 8 (17.7%) patients and prevented further exploration in 32 (71.1%) patients and also was able to predict eucalcemia in 97.7% patients at 6 months. Thus, IOPTH was able to obviate or to ask for additional procedure in 88.8% of patients. However, in three (6.6%) patients, IOPTH would guide unnecessary exploration and in equally, that is, three (6.6%) patients may require reoperation for unidentified parathyroids.

CONCLUSION

IOPTH in adjunct with other localizing studies is very helpful for carrying out successful parathyroidectomy in uniglandular disease and predicting postoperative eucalcemia. However, more importantly, its role is valuable in equivocal imaging, in such cases, it prevents unnecessary exploration or helps in adequate parathyroidectomy.

Intra-Operative Parathyroid Hormone Assay for Simplified Localization of Parathyroid Adenomas

Lack of success in parathyroid surgery is usually due to failure to identify the abnormal parathyroid gland correctly at operation. The surgeon may be helped by rapid parathyroid hormone (PTH) assay in peripheral blood after removal of a suspected adenoma, and by frozen section histology, but these are not true localization techniques. We have adapted a non-isotopic immunoassay for rapid measurement of PTH in samples from the upper, middle and lower thyroid veins taken at operation, before exploration begins. Fifteen patients with primary hyperparathyroidism were operated on. In 10 the parathyroid adenoma was located easily, and was associated with high local venous PTH levels. In four patients the abnormal parathyroid was not immediately apparent but the assay indicated its location, which was confirmed after further exploration. In one patient there was no difference in PTH levels in the six venous samples. An ectopic adenomatous gland was successfully identified behind the thymus. The operation was successful in all patients as shown by a fall in the plasma calcium to the normal range. We conclude that intra-operative selective venous sampling and rapid PTH assay facilitates operative localization of parathyroid adenomas.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Spectrum of single photon emission computed tomography/computed tomography findings in patients with parathyroid adenomas

Primary hyperparathyroidism results from excessive parathyroid hormone secretion. Approximately 85% of all cases of primary hyperparathyroidism are caused by a single parathyroid adenoma; 10–15% of the cases are caused by parathyroid hyperplasia. Parathyroid carcinoma accounts for approximately 3–4% of cases of primary disease. Technetium-99m-sestamibi (MIBI), the current scintigraphic procedure of choice for preoperative parathyroid localization, can be performed in various ways. The “single-isotope, double-phase technique” is based on the fact that MIBI washes out more rapidly from the thyroid than from abnormal parathyroid tissue. However, not all parathyroid lesions retain MIBI and not all thyroid tissue washes out quickly, and subtraction imaging is helpful. Single photon emission computed tomography (SPECT) provides information for localizing parathyroid lesions, differentiating thyroid from parathyroid lesions, and detecting and localizing ectopic parathyroid lesions. Addition of CT with SPECT improves the sensitivity. This pictorial assay demonstrates various SPECT/CT patterns observed in parathyroid scintigraphy.

Intrathyroid adenomas in primary hyperparathyroidism: are they frequent enough to guide surgical strategy?

BACKGROUND

Ectopic parathyroid adenoma, including intrathyroid adenoma, is a common cause of failed parathyroid operations. The aim of this study was to evaluate the operative strategy/outcome in patients with primary hyperparathyroidism (pHPT), with special regard to intrathyroid adenomas.

METHOD

The authors performed an analysis of all patients receiving operative treatment for pHPT from 2003 through 2005. The operative strategy consisted of systematic perithyroid exploration followed by extended cervical exploration in cases where the adenoma was not found initially. In cases of persistent, high intraoperative parathyroid hormone levels, hemithyroidectomy was performed on the side with higher suspicion of intrathyroid adenoma or with more extended thyroid changes.

RESULTS

During the study, 115 patients received surgical treatment for sporadic pHPT. A single parathyroid adenoma (normal parathyroid position) was found in 95 patients (82.6%), ectopic single adenoma was found in 7 patients (6.1%), and double adenomas were found in 10 (8.7%) patients. Operative failure occurred in 3 cases (2.6%). In all, 4 of 7 ectopic single adenomas were intrathyroidal and were removed by hemithyroidectomy according to the authors' standard protocol.

CONCLUSION

The strategy of (a) cervical exploration, (b) extended cervical exploration, and (c) hemithyroidectomy was highly successful for removing undetectable intrathyroid parathyroid adenomas during primary intervention, thereby reducing the risks associated with reintervention.

Successful removal of intrathyroidal parathyroid adenoma diagnosed and accurately located preoperatively by parathyroid scintigraphy (SPECT-CT)

We describe the case of a large intrathyroidal parathyroid adenoma in a 46-year-old woman who had a history of recently diagnosed hypercalcaemia and a 2-year history of an asymptomatic enlargement of the right lobe of the thyroid. This rare case highlights the potential difficulties that can arise in the evaluation of hyperparathyroidism, especially in cases of multinodular goiter. In some cases, including this one, even a thorough preoperative evaluation that includes radiological studies (ultrasonography and computed tomography [CT]) may not allow for a definitive preoperative diagnosis due to limited sensitivity, especially in multinodular goiter. The overlapping histological features between thyroid and parathyroid lesions can also be problematic at the time of the intraoperative frozen-section evaluation. We present a case in which, with parathyroid scintigraphy and combination of structural and functional imaging (SPECT-CT), we could accurately locate the intrathyroidal parathyroid adenoma in a patient with multinodular goiter.

Surgical management of primary hyperparathyroidism: state of the art

This article reviews the current state of the art regarding therapy for primary hyperparathyroidism. Clinical evaluation and indications for parathyroidectomy are described, followed by a review of surgical techniques currently being practiced and possible outcomes involved. Focused parathyroidectomy has become a successful alternative to conventional bilateral cervical exploration.

[Reoperation for primary hyperparathyroidism]

While the initial treatment for primary hyperparathyroidism (pHPT), if managed by an experienced surgeon, is almost always successful, reoperations are challenging. Patients are at high risk for complications and the rates of success are plainly below those of primary cervical explorations. In this paper the reasons for failure during initial procedures are reviewed, as are the most important localization procedures and the prerequisites with regard to technical infrastructure as well as personnel, when planning repeat operations for a missed parathyroid adenoma. Provided that a standardized diagnostic and surgical approach is used, the surgeon is experienced, and up-to-date technical equipment is available, permanent normocalcemia following reoperations in pHPT is more frequently achieved than it used to be. The best option to avoid reoperations and associated complications is a successful initial intervention by an experienced surgeon. However, reoperations should always be performed by an experienced surgeon.

[Reoperation for persistent or recurrent primary hyperparathyroidism. Seventy-seven cases among 1888 operated patients]

AIMS

To analyse the results of re-operations for persistent (p) or recurrent (r) primary hyperparathyroidism (PHPT).

PATIENTS AND METHODS

From 1965 throughout 2001, 1888 patients were operated on for PHPT. The cure rate after initial surgery was 97.6%. Seventy-seven (4.1%) were reoperated for p PHPT (n = 54) or r PHPT (n = 23). Thirty-two out of 77 (41%) had been primarily operated elsewhere. In 15 cases (20%) PHPT was genetically determined. The re-operation was undertaken on average 40.7 months after initial surgery (1 day-190 months).

RESULTS

Two out of 77 were cases of familial hypocalciuric hypercalcaemia. Among the 75 patients reoperated for true PHPT, 23 (31%) had uniglandular disease (UGD) and 52 (69%) had multiglandular disease (MGD). There were two cases of recurrent parathyroid carcinoma. Overall 97 pathological glands were resected, 37% being orthotopic and 63% heterotopic. The re-operation was performed by a cervical approach in 80%, by a mediastinal approach in 15%, whereas 5% involved excision of antebrachial implants. In 96% of cases the parathyroid glands were in the cervical position. Among the preoperative localisations studies the sensitivity of scintigraphy utilising 2-methoxyisobutyl-isonitril (MIBI) was 61%. Utilising both MIBI and cervical ultrasound the sensitivity was 64%. Sixty-eight out of 75 (91%) were cured of their hypercalcaemia, but at the cost of permanent hypoparathyroidism in 9% of cases. No sporadic adenoma appears to have been missed. The seven failures after re-operation (9%) involved five cases of MGD, of which four were sporadic, two cases of carcinoma and one case of parathyreomatosis. 39 patients (51%) had more than four parathyroid glands and in 22/39 cases at least one supernumerary gland was pathological.

CONCLUSION

The re-operations for PHPT were essentially due to MGD that was either sporadic or genetically determined. Often the offending supernumerary gland was not detected by imaging studies. Avoiding failures entails an initial bilateral cervicotomy with thymic exploration after MIBI scintigraphy to exclude a mediastinal focus.

Parathyroid re-exploration

Re-operative parathyroid surgery is always a challenge for the endocrine surgeon. This article discusses the issues the parathyroid surgeon must consider before and during re-operative surgery,with special attention to recently introduced adjunctive techniques.

Unilateral and bilateral surgery for parathyroid disease

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

Intraoperative parathyroid hormone assay and parathyroid reoperations

BACKGROUND

The purpose of this study was to determine whether intraoperative parathyroid hormone (IOPTH) assay improved results of reoperations.

METHODS

One hundred two patients with persistent/recurrent sporadic primary hyperparathyroidism underwent 108 reoperations (1996-2002). IOPTH was not used (n=58) from 1996-1998 (group 1). IOPTH was used (n=50) from 1999-2002 (group 2). Sensitivity and positive predictive value of IOPTH and its influence on surgical strategy were analyzed. A 50% decrease occurring 10 minutes after removal of parathyroid tumor was used to determine if all abnormal tissue had been removed.

RESULTS

Groups 1 (58 patients) and 2 (50 patients) were comparable except for duration of follow-up. The cure rate was 84% (group 1, 87%; group 2, 82%, P=0.7). Hypocalcemia developed in 20 patients (permanent in 2 patients). There was 1 permanent vocal cord paralysis and 1 patient died of toxic shock syndrome. IOPTH successfully predicted cure in 44 of 49 patients (sensitivity, 90%); the positive predictive value was 90%. Values for parathyroid hormone level and the ratio parathyroid hormone/calcium at day 1 were at least as accurate as IOPTH in predicting cure. IOPTH was helpful in 1 patient but misleading in 4 patients. It failed to modify intraoperative strategy in most other patients.

CONCLUSIONS

IOPTH testing was relatively reliable in patients with persistent or recurrent sporadic primary hyperparathyroidism, but the test unfortunately failed to improve the overall success rate at reoperation.

Usefulness of a rapid immunometric assay for intraoperative parathyroid hormone measurements

Intraoperative parathyroid hormone (IO-PTH) measurements have been proposed to improve operative success rates in primary, secondary and tertiary hyperparathyroidism (PHP, SHP and THP). Thirty-one patients requiring parathyroidectomy were evaluated retrospectively from June 2000 to January 2002. Sixteen had PHP, 7 SHP and 8 THP. Serum samples were taken at times 0 (before resection), 10, 20 and 30 min after resection of each abnormal parathyroid gland. Samples from 28 patients were frozen at -70 C for subsequent tests, whereas samples from three patients were tested while surgery was being performed. IO-PTH was measured using the Elecsys immunochemiluminometric assay (Roche, Mannheim, Germany). The time necessary to perform the assay was 9 min. All samples had a second measurement taken by a conventional immunofluorimetric method. We considered as cured patients who presented normocalcemia in PHP and THP, and normal levels of PTH in SHP one month after surgery and who remained in this condition throughout the follow-up of 1 to 20 months. When rapid PTH assay was compared with a routine immunofluorimetric assay, excellent correlation was observed (r = 0.959, P < 0.0001). IO-PTH measurement showed a rapid average decline of 78.8% in PTH 10 min after adenoma resection in PHP and all patients were cured. SHP patients had an average IO-PTH decrease of 89% 30 min after total parathyroidectomy and cure was observed in 85.7%. THP showed an average IO-PTH decrease of 91.9%, and cure was obtained in 87.5% of patients. IO-PTH can be a useful tool that might improve the rate of successful treatment of PHP, SHP and THP.

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.

Radioguided surgery in primary hyperparathyroidism

Surgical neck exploration is usually made in primary hyperparathyroidism (PHPT). Localization of the adenoma or detection of hyperplasia may reduce the operation period and limit the extent of the surgery. In this study the effficacy of preoperative Tc-99m MIBI scintigraphy and intraoperative gamma probe was evaluated.

MATERIALS AND METHODS

Six patients with PHPT had preoperative Tc-99m MIBI parathyroid scintigraphy and intraoperative gamma probe (IGP) was used in surgical neck exploration.

RESULTS

Parathyroid adenoma was observed in 2/6 patients on scintigraphy in the right retroclavicular region and the left lobe of the thyroid. Both of them were clearly detected by IGP during the surgery and easily removed by the surgeon in a short time (35 min) with a small incision. Pathologic examination confirmed the parathyroid adenoma. No abnormal MIBI uptake was not observed in scintigraphy in 4/6 patients. Subtotal parathyroidectomy was performed in these patients.

CONCLUSION

Preoperative Tc-99m MIBI scintigraphy and the use of IGP may limit the exploration and also the operation time and reduce surgical complications.

Ectopic parathyroid adenomas located at the carotid bifurcation: the role of preoperative Tc-99m MIBI scintigraphy and the intraoperative gamma probe procedure in surgical treatment planning

PURPOSE

The prevalence of ectopic parathyroid adenoma (PA) is relatively low, despite some studies in which it has been reported to be as high as 20%. Ectopic PA is a frequent cause of surgical failure, and therefore some authors recommend preoperative imaging to localize the condition in patients with primary hyperparathyroid (HPT) disease before initial surgery.

METHODS

Two unusual cases of primary HPT caused by an ectopic PA located at the carotid bifurcation are reported. The patients were examined before operation using Tc-99m MIBI scintigraphy and then underwent radioguided surgery using the intraoperative gamma probe technique with injection of a low dose (37 MBq; 1 mCi) of Tc-99m MIBI.

RESULTS

The first patient had a history of primary HPT and coexisting multinodular goiter. She had undergone total thyroidectomy in another center, but no enlarged parathyroid gland was found at bilateral neck exploration and serum calcium and parathyroid hormone levels remained elevated after intervention. The patient was referred to our center. A Tc-99m MIBI scan showed a focus of abnormal tracer uptake in the superior left laterocervical region that was thought to be a PA. The next day she underwent radioguided surgery and an 18-mm PA located at the left carotid bifurcation was easily removed through a 2.5-cm skin incision. The second patient was examined in our center before surgery. A neck ultrasound showed a multinodular goiter but no enlarged parathyroid glands. A pertechnectate-MIBI subtraction scan revealed a focus of abnormal Tc-99m MIBI uptake in the right superior laterocervical region that was thought to be a PA. One week later, at radioguided surgery, a 25-mm PA was identified at the right carotid bifurcation and removed successfully.

CONCLUSIONS

These data strongly support the utility of preoperative imaging with Tc-99m MIBI in patients with primary HPT before initial neck exploration with the aim of avoiding surgical failure. Furthermore, the intraoperative gamma probe technique seems to be useful to reduce surgical trauma and, possibly, complications in patients with ectopic PA.

99mTc-MIBI Radioguided Surgery for Limited Invasive Parathyroidectomy

We report the preliminary results obtained with the intraoperative MIBI-guided gamma probe in a group of 9 patients with primary hyperparathyroidism (pHPT). These patients were selected for limited invasive parathyroid surgery on the basis of a preoperative imaging protocol consisting of a pertechnetate & perchlorate/MIBI scan combined with neck ultrasonography (US). In the operating room 50–70 MBq MIBI was injected 30 to 45 min before parathyroidectomy. The radioactivity was measured intraoperatively at three sites: parathyroid (P), thyroid (T), and background (B). The P/B, P/T, and T/B ratios were calculated. The T/B ratio was relatively constant (range, 1.5–1.8; mean, 1.6), while a wide variability was observed both for P/T ratio (range, 1.2–2.3; mean, 1.7) and P/B ratio (range, 2.1–4.0; mean, 2.9). At surgery single enlarged parathyroid glands were easily identified by means of intraoperative MIBI-guided gamma probe. Moreover, the gamma probe allowed us to perform a limited 2–2.5 cm neck incision in eight patients affected by parathyroid adenoma. In the remaining patient a parathyroid carcinoma was diagnosed and a bilateral neck exploration was performed. The intraoperative MIBI gamma probe seems to be a useful aid when limited invasive parathyroid surgery is performed.

Improved success rate in reoperative parathyroidectomy with intraoperative PTH assay

OBJECTIVE

The clinical usefulness of preoperative localization and intraoperative PTH assay (QPTH) in primary hyperparathyroidism have been established. However, without the use of QPTH, the parathyroidectomy failure rate remains 5% to 10% in large reported series and is probably much higher in the hands of less experienced parathyroid surgeons. Persistent hypercalcemia requires another surgical procedure. The authors compared the outcomes in 50 consecutive patients undergoing more difficult secondary parathyroidectomy with and without the adjunctive support of QPTH.

METHODS

Two groups of similar patients underwent reoperative parathyroidectomy for failed surgery or recurrent disease. The successful return to normocalcemia in group I, with QPTH used to localize and confirm complete excision of all hyperfunctioning glands, was compared with group II, who did not have this intraoperative adjunct.

RESULTS

In 31/33 patients in group I, calcium levels returned to normal. With good preoperative localization studies, 17 patients underwent successful straightforward parathyroidectomies as predicted by QPTH. In the other 14 patients, QPTH assay proved extremely beneficial by facilitating localization with differential venous sampling; measuring the increase in hormone secretion after massage of specific areas; recognizing suspicious nonparathyroid tissue excised without a decrease in hormone levels, avoiding frozen-section delay; and correctly identifying the excision of abnormal tissue despite false-positive/false-negative sestamibi scans. In group II, who underwent surgery before QPTH was available, 4 of 17 patients (24%) remained hypercalcemic after extensive reexploration.

CONCLUSION

With the intraoperative hormone assay used to facilitate localization and confirm excision of all hyperfunctioning tissue, the success rate of reoperative parathyroidectomy has improved from 76% to 94%.

Minimally invasive radioguided parathyroidectomy in the reoperative neck

BACKGROUND

Operations for hyperparathyroidism (HPT) in a previously operated neck present a significant challenge and carry much higher morbidity rates than first-time operations. Our extensive experience with minimally invasive radioguided parathyroidectomy (MIRP) for first-time surgery for HPT has shown this method to be a directed approach to the offending adenoma, suggesting that the technique could be used to minimize reoperative neck surgery as well.

METHODS

Over an 11-month period 24 consecutive patients with primary HPT who had undergone at least one previous neck operation were referred for re-exploration. All patients underwent preoperative sestamibi scanning; 21 localized sufficiently to undergo MIRP.

RESULTS

All patients were cured after reoperation. Eighteen patients underwent MIRP under local anesthesia as outpatients; 3 MIRPs were done under general anesthesia. Average total operative time was 44 minutes, average incision length was 3.0 cm +/- 0.2 cm. Nineteen of the procedures were completed without any frozen sections. There were no complications.

CONCLUSION

MIRP is extremely effective in patients with HPT who have undergone previous neck exploration for parathyroid or thyroid disease. The technique allows for such a directed dissection that smaller incisions and local anesthesia in an outpatient setting are routine.

Re-operative surgery for recurrent or persistent primary hyperparathyroidism

BACKGROUND

While initial surgery for primary hyperparathyroidism, in experienced hands, will result in a cure in 98% of cases, re-operative surgery remains a significant challenge. Because attitudes as to who should perform initial exploration for hyperparathyroidism are significantly different around the world, the approach to re-operative surgery may also vary. The aim of the present study was to examine a local experience of re-operative surgery for recurrent or persistent primary hyperparathyroidism.

METHODS

Information on indications for surgery, the procedure performed, pathology and complications of all re-operative procedures for primary hyperparathyroidism in the period January 1962 to December 1996 were obtained from a prospective database.

RESULTS

Sixteen patients with persistent (n = 12) or recurrent (n = 4) primary hyperparathyroidism were treated in the unit over the study period. Eight patients had their initial operation within the unit at Royal North Shore Hospital and eight were referred from elsewhere for re-operation. Nine of the 12 patients with persistent hyperparathyroidism were cured by re-operation with failures due to spillage at first operation (n = 1) or failure to find any additional pathology (n = 2). All four patients with recurrent hyperparathyroidism were cured. All the failures occurred early in the learning phase of the unit, with a 100% cure rate for re-operative procedures performed in the last 15 years. The most common finding in patients referred from elsewhere with a failed initial operation was a missed inferior adenoma in association with the thymus. Localization studies had a variable sensitivity, with sestamibi scintigraphy, selective venous sampling and ultrasonography providing the most reliable information.

CONCLUSIONS

Re-operative surgery for persistent or recurrent hyperparathyroidism is an uncommon procedure in Australia when compared to major centres in the USA. Successful surgery depends upon experience and an accurate knowledge of the embryology and anatomy of the parathyroid glands.

Intraoperative nuclear guidance in benign hyperparathyroidism and parathyroid cancer

The success of parathyroid surgery is determined by the identification and removal of all hyperactive parathyroid tissue. Ectopic location of parathyroid tumours and fibrosis due to previous operations can cause failure of parathyroidectomy. Parathyroid tumours accumulate and retain 2-methoxyisobutylisonitrile (MIBI) labelled with technetium-99m. This study assesses the value of intra-operative localization of parathyroid tumours using a hand-held gamma detector in patients with hyperparathyroidism and parathyroid cancer. Twenty patients undergoing their first operations for hyperparathyroidism, 15 patients undergoing reoperations for either persistent or recurrent hyperparathyroidism and two patients with parathyroid cancer were studied. Radioactivity in the neck and the mediastinum was recorded by a gamma detector after administration of 370 MBq 99m Tc-MIBI. Surgical findings and postoperative serum levels of calcium were documented. The sensitivity of the gamma detector in identifying parathyroid tumours was 90.5% in first parathyroidectomies, 88.9% in reoperations for either persistent or recurrent hyperparathyroidism and 100% in parathyroid cancer. One false-positive result was due to a thyroid nodule. Hypercalcaemia ceased in all but one patient postoperatively. It is concluded that employment of the gamma detector is to be advocated in first parathyroidectomies when a parathyroid tumour cannot be discovered, in reoperations for either persistent or recurrent hyperparathyroidism and in surgery for parathyroid cancer.

Parathyroidectomy in the west Midlands

A retrospective audit was made of 101 patients undergoing parathyroidectomy, performed by 20 general surgeons in the West Midlands region during 1992. The mean number of cases per surgeon was five; nine surgeons performed fewer than three parathyroidectomies. Some 57 patients had primary hyperparathyroidism. Only seven were diagnosed by general practitioners and referral was invariably to a non-endocrine physician. Delay between diagnosis and surgical referral exceeded 2 years in 12 patients. Four patients (7 per cent) with primary hyperparathyroidism remained hypercalcaemic after first exploration; all were operated on by surgeons who performed fewer than four parathyroidectomies per year. Minor complications occurred in 32 per cent of patients. All 44 patients with renal hyperparathyroidism were treated in specialist units where diagnosis and treatment were expeditious; parathyroidectomy was successful in 41. Hyperparathyroidism should be managed in specialized units and by surgeons who perform parathyroidectomy frequently. A heightened awareness of primary hyperparathyroidism is required at primary care level.