Strategy in reoperative surgery for hyperparathyroidism

Volume-outcome relationship in parathyroid surgery

BACKGROUND

Since its first description, several studies have highlighted the role of the surgeon's experience in the outcome of parathyroid surgery, however, no uniform consensus exists regarding the minimum operative experience required for good surgical outcomes. This work aims to summarize the current data regarding the surgeon volume-outcome relationship for parathyroidectomy.

METHODS

An electronic literature review identified 85 publications, and after study selection 11 were included. An additional nine publications were added based on reference review and inclusion of publications not initially captured.

CONCLUSIONS

There are insufficient data to dogmatically conclude a minimum number of cases required to achieve optimal surgical results. However, extrapolation from the inclusive studies support the conclusions that higher operative volumes improve cure rates and decrease the rates of complications, recurrent disease, and perioperative costs. Endocrine Surgery fellowships or mentorships may help prepare the less experienced surgeon for successful outcomes. Although reticent to offer firm minimal volume requirements, we have made suggestions in this manuscript.

Thallium-Technetium Subtraction Scintigraphy of Enlarged Parathyroid Glands after Calcitonin Stimulation of Parathyroid Hormone Secretion

To improve the sensitivity of thallium-technetium subtraction scintigraphy for preoperative localization procedure of enlarged parathyroid glands in primary hyperparathyroidism, we administered calcitonin intramuscularly 4 hours before the scintigraphy in 14 consecutive patients. Injection of calcitonin reduced plasma levels of ionized calcium from 1.47 ± 0.10 mmol/l to 1.41 ± 0.09 mmol/l (p < 0.01). Concomitantly, serum levels of intact parathyroid hormone increased from 6.4 ± 2.5 pmol/l to 7.9 ± 2.6 pmol/l (p < 0.001). The scintigram after calcitonin injection visualized 11 adenomas (sensitivity 78%) compared to only 9 (sensitivity 64%) in conventional scintigrams. In addition, 5 of the adenomas were more distinctly imaged in the scintigram after calcitonin injection, whereas in only one patient was the conventional scintigram better. Thus, the calcitonin injection improved the scintigram in 7 cases and was inferior in only one case (p = 0.031). We conclude that stimulation of parathyroid hormone secretion with calcitonin results in a better preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism.

Cost-benefit analysis of the intraoperative parathyroid hormone assay in primary hyperparathyroidism

BACKGROUND

The purpose of this study was to evaluate the usefulness of the routine intraoperative intact parathyroid hormone (IOPTH) assay, the role of unilateral and bilateral cervical exploration and of preoperative imaging, and to do a cost-benefit analysis in parathyroidectomy for primary hyperparathyroidism.

METHODS

Two hundred sixty-four patients who underwent operations between January 2000 and March 2015 were retrospectively divided into 2 groups.

RESULTS

Group A (IOPTH) was composed of 64 patients. Ultrasonography and technetium-99m-sestamibi (MIBI) identified the adenoma in 38 cases. Bilateral exploration was performed in 43 patients; of which 2 failures occurred. The IOPTH false-negative rate was 18.4%. The average cost was €1297.30. Group B (without IOPTH) was composed of 200 patients. Ultrasonography and MIBI identified the adenoma in 113 cases. Bilateral exploration was performed in 129 patients; of which 2 failures occurred. The average cost was €618.75.

CONCLUSION

The IOPTH assay should be used only in few selected cases because of its high cost. The experience of the team is essential to obtain a high cure rate. © 2016 Wiley Periodicals, Inc. Head Neck 39: 241-246, 2017.

What Can We Learn from Intraoperative Parathyroid Hormone Levels that Do Not Drop Appropriately?

BACKGROUND

Parathyroidectomy remains the only definitive treatment for primary hyperparathyroidism. We studied our large series of parathyroidectomies to identify factors predictive of failure to meet intraoperative parathyroid hormone (IOPTH) monitoring criteria.

METHODS

We performed a retrospective cohort review of patients who underwent initial parathyroidectomy for primary hyperparathyroidism with IOPTH monitoring. Primary outcome was intraoperative failure, defined as failure to decrease IOPTH by ≥50 % and into normal range. Univariate and multivariate analyses were performed to determine factors associated with intraoperative failure. A subset analysis evaluated 6-month outcomes.

RESULTS

Of 2,185 subjects, 5.0 % (n = 110) experienced intraoperative failure. The intraoperative failure group had more multigland disease (35.2 vs. 16.6 %, p < 0.001) and smaller glands (1.3 vs. 1.5 cm, p = 0.048) compared to patients who experienced intraoperative success. On multivariate analysis, PTH level was statistically, but not clinically, significantly associated with intraoperative failure (odds ratio 1.0, 95 % confidence interval 1.000-1.003). Persistent hyperparathyroidism was identified in 2.5 % (n = 15) of 592 patients with ≥6 month follow-up. Median IOPTH decrease was lower in patients with persistent hyperparathyroidism (67.1 vs. 85.8 %, p < 0.001). IOPTH criteria were 93.7 % sensitive and 40.0 % specific for eucalcemia 6 months postoperatively. Of 15 patients with persistent hyperparathyroidism, 7 underwent reoperation with a 100 % cure rate. Reoperative diagnoses included ectopic mediastinal glands (n = 3), hyperplasia (n = 3), and missed second adenoma (n = 1).

CONCLUSIONS

Intraoperative failure is associated with higher rates of multigland disease and smaller parathyroid glands. Patients with persistent disease had significantly lower decreases in IOPTH, but half of patients who experienced failure by IOPTH criteria were eucalcemic 6 months postoperatively. All patients undergoing reoperation experienced successful cure.

Planar scintigraphy with 123I/99mTc-sestamibi, 99mTc-sestamibi SPECT/CT, 11C-methionine PET/CT, or selective venous sampling before reoperation of primary hyperparathyroidism?

All patients with primary hyperparathyroidism should undergo localization studies before reoperation, but it is not known which method is most accurate. The purpose of this prospective study was to compare the performance of planar scintigraphy with (123)I/(99m)Tc-sestamibi, (99m)Tc-sestamibi SPECT (SPECT/CT), (11)C-methionine PET/CT, and selective venous sampling (SVS) in persistent primary hyperparathyroidism.

METHODS

Twenty-one patients referred for reoperation of persistent hyperparathyroidism were included and investigated with (123)I/(99m)Tc-sestamibi, SPECT/CT (n = 19), (11)C-methionine PET/CT, and SVS (n = 18) before reoperation. All patients had been operated on 1-2 times previously because of hyperparathyroidism. The results of the localization studies were compared with operative findings, histology, and biochemical cure.

RESULTS

Eighteen (86%) of 21 patients were biochemically cured. Nineteen parathyroid glands (9 adenomas, 1 atypical adenoma, and 9 hyperplastic glands) were removed from 17 patients, and 1 patient who was biochemically cured had an unclear histology result. The accuracy for localizing a pathologic parathyroid gland to the correct side of the neck was 59% (95% confidence interval [CI], 36%-79%) for (123)I/(99m)Tc-sestamibi, 19% (95% CI, 5%-42%) for SPECT/CT, 65% (95% CI, 43%-84%) for (11)C-methionine PET/CT, and 40% (95% CI, 19%-65%) for SVS (P < 0.01 for (123)I/(99m)Tc-sestamibi vs. SPECT/CT). The corresponding accuracy for the correct quadrant or more specific site was 48% (95% CI, 27%-69%) for (123)I/(99m)Tc-sestamibi, 14% (95% CI, 3%-36%) for SPECT/CT, 61% (95% CI, 39%-80%) for (11)C-methionine PET/CT, and 25% (95% CI, 9%-49%) for SVS (P < 0.02 for (123)I/(99m)Tc-sestamibi vs. SPECT/CT). In the 3 patients not cured, preoperative (123)I/(99m)Tc-sestamibi and SPECT/CT remained negative, SVS was false predictive in all, and (11)C-methionine PET/CT in 1. (11)C-methionine PET/CT accurately revealed the pathologic gland in 4 of 8 (50%) patients with a negative (123)I/(99m)Tc-sestamibi scan result, all of whom were biochemically cured after reoperation.

CONCLUSION

Planar scintigraphy with (123)I/(99m)Tc-sestamibi performs well in complicated primary hyperparathyroidism and is recommended as first-line imaging before reoperation. (11)C-methionine PET/CT provides valuable additional information if (123)I/(99m)Tc-sestamibi scan results remain negative. (99m)Tc-sestamibi SPECT/CT and SVS provide no additional information, compared with the combined results of (123)I/(99m)Tc-sestamibi and (11)C-methionine PET/CT imaging.

Reoperations for primary hyperparathyroidism--improvement of outcome over two decades

PURPOSE

Reoperations (R-PTX) for primary hyperparathyroidism (pHPT) are challenging, since they are associated with increased failure and morbidity rates. The aim was to evaluate the results of reoperations over two decades, the latter considering the implementation of Tc(99m)sestamibi-SPECT (Mibi/SPECT), intraoperative parathormone (IOPTH) measurement, and intraoperative neuromonitoring (IONM).

PATIENTS AND METHODS

Data of 1,363 patients who underwent surgery for pHPT were retrospectively analyzed regarding reoperations. Causes of persistent (p) pHPT or recurrent (r) pHPT, preoperative imaging studies, surgical findings, and outcome were analyzed. Data of patients who underwent surgery between 1987 and 1997 (group 1; G1) and between 1998 and 2008 (group 2; G2) with the use of Mibi/SPECT, IOPTH, and IONM were evaluated.

RESULTS

One hundred twenty-five patients with benign ppHPT (n = 108) or rpHPT (n = 17) underwent reoperations (R-PTX). Group 1 included 54, group 2 71 patients. Main cause of ppHPT (G1 = 65 % vs. G2 = 53 %) and rpHPT (G1 = 80 % vs. G2 = 60 %) was the failed detection of a solitary adenoma (p = 0.2). Group 1 patients had significantly less unilateral/focused neck re-explorations (G1 = 23 % vs. G2 = 57 %, p = 0.0001), and more sternotomies (G1 = 35 vs. G2 = 14 %, p = 0.01). After a median follow-up of 4 (range 0.9-23.4) years, reversal of hypercalcemia was achieved in 91 % (G1) and in 98.6 % in group 2 (p = 0.08, OR 7.14 [0.809-63.1]). The rates of permanent recurrent laryngeal nerve palsy (G1 = G2 = 9 %, p = 1) and of postoperative permanent hypoparathyroidism (G1 = 9 % vs. G2 = 6 %, p = 0.5) were not significantly different. Other complications such as wound infection, postoperative bleeding, and pneumonia were significantly lower in group 2 (p < 0.001).

CONCLUSION

Nowadays, cure rates of R-PTX are nearly the same as in primary operations for pHPT. These results can be achieved in high-volume centers by routine use of well-established preoperative Mibi/SPECT and US in combination with IOPTH. However, morbidity is still considerably high.

Remedial operation for primary hyperparathyroidism

BACKGROUND

Remedial surgery for patients with persistent or recurrent primary hyperparathyroidism (1 degrees HPT) remains a significant challenge. Cervical reexploration is technically difficult; reoperative neck anatomy is distorted by fibrosis and, as a result, remedial 1 degrees HPT patients carry an increased risk of injury to the recurrent (RLN) and superior laryngeal nerve(s) as well as to normal residual parathyroid tissue. Causative hyperfunctioning parathyroid tissue is also more frequently ectopic in the remedial setting and can thus be difficult to localize.

METHODS

This report assimilates the current data underlying preoperative, intraoperative and postoperative remedial 1 degrees HPT management and presents an evidence-based algorithm for the management of remedial parathyroid disease. Recommendations are graded according to the quality of supporting data using the system initially developed by Sackett (Chest 95:2S-4S, 1989) and subsequently modified by Heinrich et al. (Ann Surg 243:154-168, 2006).

RESULTS

Recent advances in preoperative localization and intraoperative adjuncts have lead to substantial improvements in outcomes after remedial surgery. Preoperative localization techniques, including sestamibi scintigraphy (MIBI), high resolution ultrasound (US), US-guided fine needle aspiration (FNA) and selective venous sampling (SVS), coupled with intraoperative adjuncts such as the rapid parathyroid hormone (PTH) assay have lead to reoperative cure rates as high as 96 percent. Nonetheless, management of remedial 1 degrees HPT varies significantly between surgeons and no formal recommendations standardizing the care of these patients have been published.

CONCLUSIONS

Despite the significant challenges associated with remedial surgery for 1 degrees HPT, excellent outcomes can be reproducibly achieved when proper pre-, intra-, and postoperative management is employed.

Reoperation for parathyroid adenoma: a contemporary experience

BACKGROUND

We reviewed reoperations for persistent or recurrent sporadic parathyroid adenoma to evaluate and compare our current results and outcomes to our previous experience.

METHODS

From 1996 to 2008, 237 patients with persistent or recurrent hyperparathyroidism after failed operation underwent reoperation. Patients were re-explored with the assistance of non-invasive and sometimes invasive imaging.

RESULTS

A missed adenoma was suspected pre-operatively in 163 patients. Reoperation resulted in long-term resolution of hypercalcemia in 92%. Adenomas were in entopic locations in 32%; the most frequent ectopic location was the thymus (20%). Sestamibi scanning and ultrasonography were the most successful non-invasive imaging studies (96% positive predictive value (PPV) and 84% PPV respectively). Forty-four percent of patients had a reoperation based solely on non-invasive imaging. Of the invasive procedures performed, arteriography resulted in the best localization (92% PPV). Permanent recurrent laryngeal nerve injury occurred in 1.8%.

CONCLUSION

Compared to our prior experience (1982-1995), outcomes remained similar (92% resolution of hypercalcemia and 1.8% recurrent nerve injury currently versus 96% and 1.3% previously). Fewer patients received invasive studies for pre-operative localization (56% vs 73%, respectively). The decreased use of invasive imaging is due to technical improvements and greater confidence in the combination of ultrasonography and sestamibi scanning.

The management of thyroid nodules in patients with primary hyperparathyroidism

BACKGROUND

Thyroid nodules are found in 12-52% of patients with primary hyperparathyroidism (pHPT). With the increasing use of minimally invasive parathyroidectomy (MIP), there is no standard approach for the management of incidental thyroid nodules in pHPT patients.

METHODS

A survey was conducted of the American Association of Endocrine Surgeons. Information was obtained regarding parathyroidectomy practice patterns, including surgical technique, preoperative localization procedures, and algorithms used in the diagnosis/treatment of incidental thyroid nodules.

RESULTS

The survey response rate was 74%. Sixty-seven percent were high-volume parathyroid surgeons (>5/mo); the majority performed MIP. High-volume surgeons were more likely to use Sestamibi/single photon emitted computed tomography for preoperative localization (40% versus 24%; P = 0.011) and to disregard incidentally discovered thyroid nodules <1 cm (41% versus 22%; P = 0.023). They were less likely to evaluate nodules discovered intraoperatively by frozen section (28% versus 41%; P = 0.081), fine-needle aspiration (13% versus 24%; P = 0.078), or thyroidectomy (24% versus 40%; P = 0.03). Surgeons performing open parathyroidectomy were more likely than those who use MIP to biopsy nodules intraoperatively (32% versus 20%; P < 0.05) and perform simultaneous thyroidectomy (30% versus 10%; P < 0.001).

CONCLUSIONS

Experienced endocrine surgeons disagree about the optimal management of incidental thyroid nodules encountered during parathyroidectomy. Our data suggest that high-volume parathyroid surgeons are less aggressive in their evaluation of thyroid pathology in patients with pHPT. Variation in practice among this experienced group implies even greater variation in the broader surgical community, and in the quality and cost of care for patients with pHPT.

Remedial surgery for primary hyperparathyroidism

Remedial parathyroid surgery is a complex undertaking for even the most experienced parathyroid surgeon. It involves a careful preoperative evaluation, including the confirmation of the initial diagnosis of primary HPTH, use of the appropriate localization studies, knowledge of the details of the previous exploration, and surgical re-exploration, including the use of intraoperative localization adjuncts, such as the rapid intraoperative PTH assay (Fig. 6). Althoughthe success rate of remedial explorations can be as high as 98%, complication rates are higher than in initial cervical explorations for parathyroid disease.

[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.

Accuracy of selective venous sampling for intact parathyroid hormone in difficult patients with recurrent or persistent hyperparathyroidism

BACKGROUND

Preoperative noninvasive localization studies of the neck and mediastinum are beneficial before reoperation. However, the role of selective venous sampling (SVS) for parathyroid hormone (PTH) in reoperative parathyroid surgery has never been clearly defined. The purpose of this study was to evaluate the accuracy of SVS when applied selectively to the subset of patients with indeterminate noninvasive localization studies.

METHODS

Between January 1990 and December 2001, 64 of 235 (27%) patients with persistent or recurrent hyperparathyroidism were considered candidates for SVS in addition to noninvasive localization studies. Accuracy of SVS for PTH was retrospectively evaluated.

RESULTS

Successful surgical treatment was achieved in 86% of these patients. SVS for PTH yielded true-positive results in 75% of patients and was not useful for the surgeon in 17% (completely false-positive in 12% and indeterminate in 5%). In 2% of patients, SVS identified successfully 1 gland but failed to locate another abnormal gland. In 6% of patients, the location of the abnormal parathyroid tissue remained unknown, and the patients have persistent hyperparathyroidism.

CONCLUSIONS

We showed that SVS is clinically useful in patients with persistent or recurrent hyperparathyroidism when the noninvasive localization studies do not clearly localize the abnormal parathyroid glands.

Measurement of parathyroid hormone in patients with primary hyperparathyroidism undergoing first and reoperative surgery

BACKGROUND

The distinction between solitary parathyroid adenoma and hyperplasia can sometimes be difficult during surgery for primary hyperparathyroidism (pHPT), especially in patients who have undergone previous thyroid or parathyroid surgery. The use of intraoperative parathyroid hormone (PTH) monitoring as a possible diagnostic tool was therefore investigated.

METHODS

Intraoperative levels of PTH were measured in 119 patients during 121 operations (including 14 reoperations) for pHPT. The mean(s.d.) preoperative serum calcium level was 2.79(0.21) mmol/l. Blood samples were drawn before, and at 5 and 15 min after, excision of the first enlarged parathyroid gland. PTH was analysed electively in 61 patients and on-line by a modified assay for intact PTH in 48 patients. Both procedures were used in ten patients.

RESULTS

The mean(s.d.) decline in PTH concentration in 101 patients with primary exploration due to solitary adenoma was 63(17) per cent after 5 min (n=84) and 83(10) per cent after 15 min. The patients with primary exploration because of multiglandular disease (n=6) were correctly predicted not to have parathyroid adenoma.

CONCLUSION

Measurement of PTH levels during surgery for pHPT is a highly sensitive method for differentiating between single and multiple gland disease. The on-line monitoring of PTH is clinically useful in patients who have undergone previous neck surgery. Its role in pHPT surgery at primary exploration should be evaluated in prospective trials.

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.

Intrathyroidal parathyroid glands can be a cause of failed cervical exploration for hyperparathyroidism

BACKGROUND

The incidence of intrathyroidal parathyroid glands remains controversial. The purpose of this study was to determine the incidence in a series of patients with hyperparathyroidism.

METHODS

Three hundred nine patients underwent parathyroidectomy. Patients were divided into two groups: uniglandular disease versus hyperplasia.

RESULTS

Eighteen of 309 patients (6%) had abnormal intrathyroidal parathyroid glands. The incidence was 3% (7 of 222) in patients with uniglandular disease versus 15% (11 of 73) in those with hyperplasia. With a mean follow-up of 54 months, 12 patients are eucalcemic, 5 have persistent hypocalcemia, and 1 has recurrent hypercalcemia. There were no recurrent laryngeal nerve injuries.

CONCLUSIONS

These data suggest that an intrathyroidal adenoma is an uncommon cause of failure, whereas abnormal intrathyroidal parathyroid tissue may be a more common cause of failure in patients with hyperplasia.

Regional body FDG-PET in postoperative recurrent hyperparathyroidism

PURPOSE

The use of preoperative imaging studies in patients with persistent or recurrent hyperparathyroidism after initial operation is generally accepted to improve the success rate and minimize the morbidity from reoperative surgery. The purpose of this study was to define the performance of FDG-PET for the localization of hyperfunctioning parathyroid tissue prior to reoperation.

METHOD

Twenty patients with biochemical evidence of recurrent or persistent hyperparathyroidism following previous neck surgery were investigated. Regional body PET imaging of the neck and upper chest (axial field of view 27.5 cm) was acquired 45 min after 5-10 mCi FDG was given intravenously.

RESULTS

Subsequent surgery revealed solitary parathyroid adenomas in 14 patients, seven hyperplastic glands in 2 patients, and parathyroid carcinoma in 1 patients. FDG-PET correctly identified 79% (11/14) of the parathyroid adenomas, 29% (2/7) of the hyperplastic glands, and the parathyroid carcinoma. FDG-PET was negative in 79% (30/38) of the surgically identified normal parathyroid glands. Eight false-positive findings led to a positive predictive value of 64%.

CONCLUSION

These preliminary data suggest that regional body FDG-PET is a promising procedure in the evaluation of patients with persistent or recurrent postoperative hyperparathyroidism.

Parathyroidectomy in Maryland: effects of an endocrine center

BACKGROUND

Surgery for hyperparathyroidism is associated with high cure rates and low morbidity and mortality when performed by experienced surgeons. We wanted to determine whether referral of patients with hyperparathyroidism to an endocrine surgery center has an impact on patient outcomes and costs.

METHODS

Data from 901 patients who underwent parathyroidectomy recorded in the Maryland inpatient discharge database between 1990 and 1994 at 52 hospitals were compared with 169 consecutive patients who underwent surgical exploration by one surgeon (R.U.) at the Johns Hopkins Hospital.

RESULTS

Although in 47 of 52 hospitals fewer than 10 parathyroidectomies were performed each year, in these hospitals four of five related deaths occurred before patient discharge. The percentage of parathyroidectomies in Maryland performed by one endocrine surgeon has increased from 8% in 1990 to 21% in 1994 and is associated with a 97% cure rate and no mortality. Moreover, while hospital length of stay (LOS) in the state has decreased from 7 to 3.1 days, LOS for the high-volume provider has declined to a mean of 1.3 days.

CONCLUSIONS

Patients with hyperparathyroidism are increasingly referred to an endocrine surgery center, which results in a high cure rate, low morbidity, no mortality, and a shorter LOS. Improved surgical outcomes and lower costs depend on an experienced surgeon and argue for the referral of these patients to endocrine surgery centers.

Mechanism of technetium 99m sestamibi parathyroid imaging and the possible role of p-glycoprotein

BACKGROUND

Localization of parathyroid glands is critical in the treatment of recurrent or persistent hyperparathyroidism. Technetium sestamibi imaging may improve localization; however, the mechanism of visualization of parathyroid tissue remains unclear. On the basis of the chemical structure of sestamibi it has been suggested that p-glycoprotein is involved in the transport of sestamibi across cell membranes. This study was designed to examine sestamibi uptake and retention and p-glycoprotein expression in normal and abnormal parathyroid tissue.

METHODS

Thirty-two consecutive patients underwent 2-methoxy-isobutyl-isonitrile imaging immediately before parathyroid exploration. Tissue was obtained from normal and abnormal parathyroids and from the thyroid gland. Touch preparations gave rapid confirmation of tissue origin. Specimens were trimmed and weighed, and gamma-emission was counted. Percentage injected dose per gram of tissue was calculated. Immunohistochemistry was obtained with a battery of monoclonal antibodies to identify p-glycoprotein in parathyroid tissue submitted for permanent histologic examination. Slides were graded by a pathologist familiar with immunohistochemistry.

RESULTS

Abnormal parathyroid tissue had a higher mean retention of injected dose per gram than did normal thyroid and parathyroid tissue. Immunohistochemistry revealed that abnormal parathyroid tissue expresses less p-glycoprotein.

CONCLUSIONS

These results suggest that size is not the single determinant of parathyroid visualization and that p-glycoprotein expression may be involved in the mechanism of parathyroid imaging.

A prospective trial evaluating a standard approach to reoperation for missed parathyroid adenoma

OBJECTIVES

The authors evaluate the results of preoperative imaging protocols and surgical re-exploration in a series of patients with missed parathyroid adenomas after failed procedures for primary hyperparathyroidism.

BACKGROUND

The success rate is lower and the complication rate is increased in patients undergoing reoperation for primary hyperparathyroidism compared with initial procedures. Scarring and distortion of tissue planes plus the potential for ectopic gland location leads to this worsened outcome.

METHODS

Two hundred eighty-eight consecutive patients with persistent/recurrent hyperparathyroidism were treated at a single institution after a failed procedure or procedures at outside institutions. Two hundred twenty-two of these patients (77%) were believed to have a missed single adenoma, and these patients underwent 228 operations and 227 preoperative work-ups. Preoperative evaluation consisted of a combination of four noninvasive imaging studies--neck ultrasound, nuclear medicine scan, neck and mediastinal computed tomography scan, and neck and mediastinal magnetic resonance imaging. Based on the noninvasive testing alone, 27% patients underwent surgery whereas the other patients underwent invasive studies, including selective angiography (58%), selective venous sampling for parathyroid hormone (43%), or percutaneous aspiration of suspicious lesions (15%).

RESULTS

Abnormal parathyroid adenomas were found in 209 of 222 initial procedures and 6 of 6 second procedures, with an overall success rate in terms of resolution of hypercalcemia in 97% (215/222) of patients. The single most common site of missed adenoma glands was in the tracheal-esophageal groove in the posterior superior mediastinum (27%). The most common ectopic sites for parathyroid adenomas are thymus (17%), intrathyroidal (10%), undescended glands (8.6%), carotid sheath (3.6%), and the retroesophageal space (3.2%). The most sensitive and specific noninvasive imaging test is the sestamibi subtraction scan, with 67% true-positive and no false-positive results. The rate of true-positive and false-positive results for ultrasound, computed tomography, magnetic resonance imaging, and technetium thallium scans were 48%/21%, 52%/16%, 48%/14% and 42%/8%, respectively. The incidence of injury to the recurrent laryngeal nerve was 1.3%.

CONCLUSIONS

A single missed parathyroid adenoma is the most common cause for a failed initial parathyroid operation. Appropriate use of preoperative imaging tests and knowledge of the potential location or parathyroid adenomas can lead to very high cure rates with minimal morbidity.

Persistent or recurrent hyperparathyroidism in patients with double adenomas

BACKGROUND

Are double parathyroid adenomas a discrete clinical entity or are all hyperplastic parathyroid glands of varying size? This investigation was done to determine whether patients with persistent or recurrent hyperparathyroidism and double adenomas (DA) differ in clinical profile or in response to treatment from patients with hyperplasia.

METHODS

From 1982 to 1993, 37 unselected patients with persistent (11) or recurrent hyperparathyroidism (26) were treated. Twenty-one had DA and 16 had hyperplasia. DAs were defined as two abnormal and two normal parathyroid glands.

RESULTS

Patients with persistent or recurrent hyperparathyroidism caused by DA were older and had more muscle weakness, neuropsychiatric disorders, constipation, and weight loss (p < 0.001) than patients with persistent or recurrent hyperparathyroidism caused by hyperplasia. Nephrolithiasis was more common in patients with recurrent hyperparathyroidism caused by hyperplasia than in patients with recurrent hyperparathyroidism caused by DA (p < 0.001). Serum Ca2+ levels before operation were similar in these groups with variable parathyroid hormone levels. No recurrences occurred in either group (DA [mean, 6 yr]; hyperplasia [mean, 5 yr]). Postoperative levels of serum Ca2+ and parathyroid hormone were normal in both groups.

CONCLUSIONS

Patients with persistent or recurrent hyperparathyroidism caused by DA are older, have different clinical manifestations, and are cured by resection of the second adenoma. These findings support the concept that DA and hyperplasia are distinct entities.

Undescended superior parathyroid gland: a potential cause of failed cervical exploration for hyperparathyroidism

BACKGROUND

The undescended inferior parathyroid gland is a well-established although infrequent embryologic abnormality resulting in an ectopically located gland usually associated with thymic tissue and is found most commonly within the carotid sheath at the level of the carotid bifurcation. Embryologically undescended superior glands (either normal or enlarged), clearly above the level of the upper pole of the thyroid gland and found within or in approximation to the lateral pharyngeal wall, have not been previously described.

METHODS

The locations of all parathyroid glands at the time of cervical exploration were carefully examined as to embryologic origin in a combined experience of more than 3000 patients with primary or secondary hyperparathyroidism.

RESULTS

Five patients had enlarged abnormal glands located within or in close approximation to the pharyngeal wall. All were above the upper pole of the thyroid gland. Two were identified at reoperation on the basis of localization studies. One gland was found after resection of a massive concomitant cervical goiter. The other two were found after an extensive search for a superior gland.

CONCLUSIONS

Undescended superior glands are extremely rare (0.08%). They are located within or in approximation to the pharynx above the level of the thyroid gland with an unusual blood supply, which supports an embryologic rather than acquired cause for their ectopic location.

Analysis of savings in operative time for primary hyperparathyroidism using localization with technetium 99m sestamibi scan

BACKGROUND

The cost effectiveness of preoperative localization in cases of primary hyperpara-thyroidism has not been established. We analyzed the potential savings in operative time after localization with technetium 99m (99mTc) sestamibi scan.

METHODS

Thirty-three patients had localization of a solitary adenoma with 99mTc-sestamibi. Measurement was made of the time required for adenomectomy, unilateral neck exploration (UNE), unilateral neck exploration and confirmation of one contralateral parathyroid gland (UNEC), or bilateral neck exploration (BNE).

RESULTS

The total operative time in minutes was 76.4 +/- 18.8 for adenomectomy; 87.5 +/- 20.4 for UNE; 105.6 +/- 25.0 for UNEC; and 117.9 +/- 26.7 for BNE. The time difference was significant between adenomectomy versus UNE, UNEC, and BNE. There were also significant time differences between UNE versus UNEC and BNE.

CONCLUSIONS

The preoperative localization of a solitary parathyroid adenoma may optimize operative time with UNE, saving approximately 30 minutes.

Localization studies in patients with hyperparathyroidism

Patients with hyperparathyroidism who have not had previous neck surgery do not require preoperative localization because of the high success rate of cervical exploration (95%) and the limited sensitivity and specificity of all imaging modalities currently in use. Successful parathyroid exploration requires knowledge of the normal and frequently encountered variations in parathyroid anatomy (Fig. 4). Experience permits recognition of often subtle multiple gland disease. In skilled surgical hands, results are excellent with minimal morbidity. When recurrent or persistent disease or previously operated patients are encountered, confirmation of the diagnosis and attempts at localization should precede operation. Technetium sestamibi SPECT imaging and ultrasonography with FNA of suspicious glands are complementary tests that are readily available, inexpensive, and well tolerated by patients. If these tests are unsuccessful, MRI, CT, and invasive procedures should be pursued until the gland is localized.

Reoperation for suspected primary hyperparathyroidism

A retrospective analysis of 93 patients undergoing 128 re-explorations for persistent or recurrent hypercalcaemia is presented. Seventy-six patients (82 per cent) became normocalcaemic after between one and five reoperations. Nine patients had hypercalcaemia caused by sarcoidosis, familial hypocalciuric hypercalcaemia or metastatic disease, and two had parathyroid carcinoma. Fifteen patients (16 per cent) developed permanent hypoparathyroidism requiring vitamin D and/or calcium therapy and nine had permanent recurrent laryngeal nerve paralysis. Undetected adenomas (41 cases) and inadequate resection in hyperplastic disease (28) were the predominant causes of initial failure. Reoperation for persistent or recurrent hyperparathyroidism restored normocalcaemia in the majority of patients. This 'cure' was achieved at the cost of considerable morbidity and a careful risk-benefit analysis of each patient is recommended before performing reoperative parathyroid surgery.

Management of primary hyperparathyroidism caused by multiple gland disease

Multiple gland parathyroid disease is the pathological finding in primary hyperparathyroidism (HPT) in about 10% to 20% of all patients and in approximately a third of all patients with persistent or recurrent disease. The variability of multiple gland disease spans from 2 adenomas to diffuse hyperplasia in patients with multiple endocrine neoplasia type 1. This variability calls into question the proposed common pathophysiologic background in all of these cases. As primary treatment of multiple gland primary HPT, subtotal parathyroidectomy and thymectomy or total parathyroidectomy and heterotopic autotransplantation including thymectomy can be equally advocated. Recurrent hyperparathyroidism frequently occurs in cases of diffuse parathyroid hyperplasia. This must be considered especially in patient follow up and before each surgical procedure. Thus, a defined but adaptable therapeutic regimen might prevent permanent hypoparathyroidism and persistent hyperparathyroidism.

Locally recurrent parathyroid neoplasms as a cause for recurrent and persistent primary hyperparathyroidism

Between 1982 and 1989, 145 patients underwent operations for persistent or recurrent primary hyperparathyroidism (HPT). At re-exploration, 15 patients (10.3%) were found to have locally recurrent parathyroid tumors (11 patients with adenoma and 4 with carcinoma). These 15 patients had 28 previous operations at outside institutions for HPT. Patients with locally recurrent HPT secondary to adenoma had a longer disease-free interval than patients with locally recurrent carcinoma. At the time of evaluation at the National Institutes of Health (NIH) for recurrent or persistent HPT, each patient was symptomatic and patients with carcinoma had significantly more symptoms and higher serum levels of calcium and parathyroid hormone than patients with adenoma. Locally recurrent parathyroid neoplasm was correctly localized by preoperative testing in 14 of 15 patients. These 15 patients underwent 18 reoperations at NIH for excision of locally recurrent parathyroid tumors. Following the final reoperation (two patients had more than one procedure), each patient had normal serum levels of calcium. In addition each patient remains biochemically cured (based on normal serum calcium level), with a median follow-up interval of 21 months. Local recurrence of parathyroid adenoma comprises a small but significant proportion of cases of recurrent or persistent HPT and can be indistinguishable from parathyroid carcinoma. Findings suggestive of carcinoma include shorter disease-free interval, higher serum levels of calcium and parathyroid hormone, and histologic appearance. Whether the locally recurrent parathyroid neoplasm is benign or malignant, aggressive surgery can control serum levels of calcium in these patients with acceptable rates of morbidity.

Initial failure of surgical exploration in patients with primary hyperparathyroidism

To determine the causes of failures of cervical exploration for primary hyperparathyroidism, we reviewed 892 patients operated on by one surgeon from 1953 to 1990. Twenty-seven patients (3%) remained hypercalcemic or developed hypercalcemia within 6 months of surgery. Of these, five patients had one adenoma removed initially; at reoperation, three patients had a second adenoma that was successfully removed, whereas the other two patients had hyperplasia and required subtotal parathyroidectomies. No enlarged parathyroid glands were identified in 22 patients. Eventually, six patients became normocalcemic spontaneously, seven patients underwent re-exploration with a successful outcome in all but one case, two patients had ectopic hyperparathyroidism associated with carcinoma elsewhere, and seven patients refused reoperation and remain hypercalcemic. The failure rate of surgical exploration for primary hyperparathyroidism can be reduced by systematically exploring all four parathyroid glands. All abnormal parathyroids should be removed with histologic verification. When no abnormal glands are found, localization studies should be performed before re-exploration.