A rising ioPTH level immediately after parathyroid resection: are additional hyperfunctioning glands always present? An application of the Wisconsin Criteria

Near-Infrared Autofluorescence Signatures of Single- vs Multigland Disease in Primary Hyperparathyroidism

Importance

The success of parathyroidectomy depends on accurate intraoperative localization and identification of all diseased glands in parathyroid exploration based on surgeon expertise to prevent persistent hyperparathyroidism. Near-infrared autofluorescence (NIRAF) imaging has recently emerged as a promising adjunctive intraoperative tool for localizing parathyroid glands; however, its potential utility in the assessment of parathyroid glands has yet to be established.

Objective

To analyze the differences in NIRAF signatures of parathyroid glands in single vs multiple glands in primary hyperparathyroidism (pHPT).

Design, Setting, and Participants

This prospective diagnostic study analyzed in vivo NIRAF images of parathyroid glands obtained during parathyroidectomies between November 18, 2019, and December 31, 2023, at a single tertiary referral center. Pixel intensities of the images were measured using third-party software. Patients who underwent parathyroidectomy for sporadic pHPT using a second-generation NIRAF imaging device were included. Patients with multiple endocrine neoplasm disorders were excluded. In vivo NIRAF images obtained during the procedures were analyzed.

Exposure

Near-infrared autofluorescence imaging during parathyroidectomy.

Main Outcomes and Measures

The primary outcomes were the autofluorescence intensity and heterogeneity of single adenomas and multigland disease (ie, double adenomas and 3- or 4-gland hyperplasia) in sporadic pHPT. Normalized autofluorescence intensity was calculated by dividing the mean pixel intensity of the parathyroid gland by the background tissue. A heterogeneity index was calculated by dividing the standard deviation by the mean pixel intensity of the gland. The secondary outcome was the visibility of each parathyroid gland on NIRAF imaging before it became apparent to the naked eye during exploration.

Results

A total of 1287 in vivo NIRAF images obtained from 377 patients (median [IQR] age, 66 [56-73] years; 299 female [79.3%]) were analyzed. Of all patients, 230 (61.0%) had a single adenoma, 91 (24.1%) had double adenomas, and 56 (14.9%) had 3- or 4-gland hyperplasia. A mean (SD) of 3.4 (1.1) parathyroid glands were identified in the procedures. A comparison of 581 diseased glands (45.1%) and 706 normal glands (54.9%) showed a lower median normalized autofluorescence intensity of 2.09 (95% CI, 1.07-4.01) vs 2.66 (95% CI, 1.43-4.20; effect size = 0.36) and higher heterogeneity index of 0.18 (95% CI, 0.07-0.41) vs 0.11 (95% CI, 0.01-0.27; effect size = 0.45), respectively. Of diseased glands, single adenomas (233 [40.1%]) vs double adenomas (187 [32.2%]) and 3- or 4-gland hyperplasia (161 [27.7%]) had a lower median autofluorescence intensity of 1.92 (95% CI, 1.02-4.44) vs 2.22 (95% CI, 1.10-3.97; effect size = 0.21), respectively. On receiver operating characteristic analysis, the optimal autofluorescence intensity threshold to differentiate between single adenomas vs multigland disease was 2.14, with a sensitivity of 64.4%, specificity of 58.1%, and area under the curve of 0.626.

Conclusions and Relevance

These findings suggest that parathyroid glands in single- vs multigland disease may exhibit different autofluorescence characteristics. Although the effect size was modest, the differences identified should be kept in mind when assessing the parathyroid glands during surgical exploration.

Complex Primary Hyperparathyroidism: Hereditary and Recurrent Disease

Primary hyperparathyroidism can be sporadic or part of a genetic syndrome, such as MEN1 or HPT-JT. Diagnosis of hereditary HPT requires a thorough history and physical. Parathyroidectomy is curative with greater than 95% success. However, some patients have persistent or recurrent disease requiring reoperation. Reoperative parathyroidectomy is technically challenging, and localizing the pathologic gland can difficult. Patients needing reoperation should undergo evaluation by a high-volume surgeon. Care should be taken to obtain all of the preoperative workup and operative note from the initial surgery. Radioguided parathyroidectomy can be safely and effectively performed in patients with hereditary HPT or undergoing reoperative surgery.

Extreme Elevation of Baseline Intraoperative Parathyroid Hormone Measurements: Should Usual Protocols Apply?

INTRODUCTION

Intraoperative parathyroid hormone (IOPTH) monitoring is routinely used to facilitate minimally invasive parathyroidectomy. Many IOPTH protocols exist for predicting biochemical cure. Some patients are found to have extremely high baseline IOPTH levels (defined in this study as >500 pg/mL), which may affect the likelihood of satisfying certain final IOPTH criteria. We aimed to discover whether clinically significant differences exist in patients with extremely high baseline IOPTH and which IOPTH protocols are most appropriately applied to these patients.

MATERIALS AND METHODS

This is a retrospective review of 237 patients who underwent parathyroidectomy with IOPTH monitoring for primary hyperparathyroidism (pHPT) from 2016 to 2020. Baseline IOPTH levels, drawn prior to manipulation of parathyroid glands, were grouped into categories labeled "elevated" (>65-500 pg/mL) and "extremely elevated" (>500 pg/mL). Final IOPTH levels were analyzed to determine whether there was a >50% decrease from baseline and whether a normal IOPTH value was achieved. 6-wk postoperative calcium levels were also examined.

RESULTS

Of the patients in this cohort, 76% were in the elevated group and 24% in the extremely elevated group. Male sex and higher preoperative PTH levels were correlated with higher baseline IOPTH levels. Patients with extremely elevated baseline IOPTH were less likely to have IOPTH fall into normal range at the conclusion of the case (P = 0.019), and final IOPTH levels were higher (P < 0.001), but the IOPTH was equally likely to decrease >50% from baseline. There was no difference in the mean postoperative calcium levels between the two groups at 6-wk or at longer term follow-up (mean 525 d).

CONCLUSIONS

Detection of baseline IOPTH levels >500 pg/mL during parathyroidectomy performed for pHPT is not uncommon. IOPTH in patients with extremely elevated baseline levels were less likely to fall into normal range, but follow-up calcium levels were equal, suggesting that applying more stringent IOPTH criteria for predicting biochemical cure may not be appropriate for this population.

Primary Hyperparathyroidism and Intraoperative Parathyroid Hormone Monitoring: Application of a Modified Interpretation in Patients With "Parathyroid Hormone Spikes"

INTRODUCTION

Intraoperative parathyroid hormone (PTH) spikes occur in up to 30% of patients during surgery for primary hyperparathyroidism. This can lead to a prolonged PTH decline and cause difficulties in using current interpretation criteria of intraoperative PTH monitoring. The aim of this study aim was to evaluate an alternative interpretation model in patients with PTH spikes during exploration.

METHODS

1035 consecutive patients underwent surgery for primary hyperparathyroidism in a single center. A subgroup of patients with intraoperative PTH spikes of >50 pg/mL were selected (n = 277; 27.0%). The prediction of cure applying the Miami and Vienna criteria was compared with a decay of ≥50% 10 min after excision of the enlarged parathyroid gland using the "visualization value" (VV; =PTH level immediately after visualization of the gland) as basal value. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated.

RESULTS

Using the VV, sensitivity was 99.2% (Vienna 71.0%; Miami 97.7%), specificity was 18.2 (Vienna 63.6%; Miami 36.4%), and accuracy was 92.8 (Vienna 70.4%; Miami 92.8%). Of 255 single-gland disease patients, 72 were identified correctly as cured by applying the VV (P < 0.001), yet 10 of 22 patients with multiple-gland disease were missed compared with the Vienna Criterion (P = 0.002). The comparison with the Miami Criterion showed that six more patients were correctly identified as cured (P = 0.219), whereas four patients with multiple-gland disease were missed (P = 0.125).

CONCLUSIONS

Using the VV as a baseline in patients with intraoperative PTH spikes may prove to be an alternative and therefore can be recommended. However, if the VV is higher than the preexcision value, it should not be applied.

Intraoperative parathormone increase after focused parathyroidectomy in a patient with sarcoidosis - Case report

Introduction

Hypercalcaemia is most commonly a sign of primary hyperparathyroidism but can also be a sign of an active granulomatous disease. Standard treatment for primary hyperparathyroidism caused by a solitary parathyroid gland adenoma identified by localisation studies is minimally invasive focused parathyroidectomy. If unsuccessful, bilateral neck exploration is recommended.

Case presentation

We report the case of hypercalcaemia and ostheoporosis in a 63-year -old woman with a history of sarcoidosis and suspected primary hyperparathyroidism. Localisation studies for parathyroid adenoma were inconclusive due to active cervical and mediastinal granulomatous lymph nodes. Sarcoidosis was treated with corticosteroids but hypercalcaemia persisted. Focused parathyroidectomy was attempted with intraoperative parathyroid hormone measurement but an increase in parathyroid hormone levels was observed. However, with high clinical probability of a successfully removed adenoma and frozen section evaluation, we decided not to proceed with bilateral neck exploration. Serum parathyroid hormone and calcium levels dropped accordingly the following day.

Clinical discussion

We explored all possible underlying mechanisms for persistent elevated parathyroid hormone level described in literature.

Conclusion

We conclude that Wisconsin Criteria with intraoperative parathyroid hormone measured 20 minutes after adenoma removal should be applied in such cases.

Prevalence of Thymic Parathyroids in Primary Hyperparathyroidism During Radioguided Parathyroidectomy

Background:

Radioguided surgery has been an effective tool for identifying hyperfunctioning parathyroid glands during routine parathyroidectomy for hyperparathyroidism. The purpose of this study was to examine the role of radioguided surgery for the identification of intrathymic parathyroid glands.

Material and Methods:

Between March 2001 and February 2018, 2291 patients underwent parathyroidectomy by 1 surgeon for primary hyperparathyroidism. Of these patients, 158 (7%) were identified to have an ectopic intrathymic parathyroid gland. All patients underwent radioguided parathyroidectomy. Ex vivo radionuclide counts were used to confirm parathyroid excision with specimen radioactivity of >20% of the background level.

Results:

The mean age was 56 ± 1 years with 74% of the patients being female. Preoperatively, 122 patients underwent sestamibi scan, which correctly identified the affected gland 61% of the time. Mean background radionuclide count was 208 ± 7, mean ex vivo radionuclide count was 127 ± 9, with ex vivo counts of removed glands >20% in all patients. All ectopic parathyroid glands were successfully identified using gamma probe. Ex vivo counts found to be significantly higher in patients with adenomas. Patients with parathyroid adenomas also were older in age and had higher preoperative calcium levels. While 10% of patients with primary hyperparathyroidism have hyperplasia, 42% of patients with thymic parathyroids had hyperplasia.

Conclusions:

Radioguided parathyroidectomy is useful in detecting ectopic parathyroid glands in the thymus. Patients with hyperplasia disproportionately have clinically significant thymic parathyroid glands.

The utility of the radionuclide probe in parathyroidectomy for primary hyperparathyroidism

INTRODUCTION Parathyroidectomy is the definitive treatment for primary hyperparathyroidism but the intraoperative identification of adenomas is challenging. The aim of this study was to evaluate the utility of a radionuclide probe (RNP) in addition to intraoperative parathyroid hormone ( IOPTH) measurement as an intraoperative diagnostic adjunct in patients undergoing parathyroidectomy for primary hyperparathyroidism. METHODS This was a retrospective cohort study of patients treated between 2004 and 2015 in a university affiliated teaching hospital. Patients were grouped into those with RNP use (RNP+) and those without (RNP-). The primary outcome measure was rate of operative failure, which included false positives. The diagnostic sensitivity and positive predictive value of both RNP and IOPTH were also evaluated. RESULTS A total of 298 patients were included in the study, 127 (42.6%) being in the RNP+ group and 171 (57.4%) in the RNP- group. The false positive rate for the RNP+ patients was 1.6% compared with 9.4% for RNP- patients (p=0.006, hazard ratio [HR]: 6.45). The rates of operative failure were 6.3% and 11.7% respectively (p=0.159, HR: 1.97). RNP use had a sensitivity of 92.0% and a positive predictive value of 98.3% compared with 78.6% and 95.2% respectively for IOPTH monitoring. CONCLUSIONS RNP use is associated with fewer false positives and reduced operative failure than IOPTH measurement. It also has a higher sensitivity and positive predictive value. RNP use is recommended in centres that have the required facilities.

MULTIGLANDULAR PARATHYROID GLAND DISEASE: AN INCIDENTAL DISCOVERY IN NORMOCALCEMIC PATIENTS DURING THYROID SURGERY

Context

Several enlarged parathyroid glands could be found during thyroid surgery in normocalcemic patients without evidence of primary or secondary hyperparathyroidism, indicating multiglandular parathyroid gland disease (MGD).

Objective

Clinical role of various levels of serum ionized calcium (Ca²⁺) in patients diagnosed with incidental MGD during thyroid surgery remains controversial. The aim of the study was to evaluate the features of PHPT and the clinical role of serum Ca²⁺ in normocalcemic patients diagnosed with incidental MGD.

Study design

A prospective study of patients with normal preoperative Ca²⁺ to be operated on for thyroid diseases in 2010-2013 and diagnosed with MGD during thyroid surgery.

Methods

An analysis of clinical data from 3,561 patients to be surgically treated for thyroid diseases revealed 219 (6%) patients with MGD and normal serum Ca²⁺. Further data analyses showed patients with MGD and high normal (≥1.25 - 1.3 mmol/L) serum Ca²⁺ (n = 89) and with moderate-low (1.0 - 1.24 mmol/L) serum Ca²⁺ (n = 130).

Results

Primary hyperparathyroidism was diagnosed intra- and post-operatively in 48 (54%) patients with high-normal serum Ca²⁺ and in 2 (2%) patients with moderate-low serum Ca²⁺ (p<0.0001). Parathyroid hormone, serum Ca²⁺ as well as urine calcium excretion were elevated in 2 (2%) patients with moderate-low serum Ca²⁺ and in 18 (20%) patients with high-normal Ca²⁺ at follow-up (p<0.0001).

Conclusion

Serum Ca²⁺ level within the normal range, but higher than 1.25 mmol/L (high-normal) is associated with primary hyperparathyroidism, which should be considered in patients with visually diagnosed MGD, but without clinical symptoms of hyperparathyroidism.

Intraoperative Parathyroid Hormone Levels at 5 min Can Identify Multigland Disease

BACKGROUND

Intraoperative parathyroid hormone (IOPTH) monitoring is crucial in the treatment of primary hyperparathyroidism (PHPT). Often, the 5 min IOPTH levels fall, but not by the requisite 50 %. In such cases, the surgeon must decide whether to wait for additional levels or to continue exploration. This study aimed to evaluate the 5 min drop in IOPTH for distinguishing single adenomas (SA) from multigland disease.

METHODS

A retrospective analysis of a prospectively collected database was performed on PHPT patients who underwent initial curative parathyroidectomy between 2001 and 2013. Those with familial disease and those taking lithium or undergoing concomitant thyroidectomy were excluded from the analysis. For cases of double adenomas (DA) or hyperplasia (HA), the IOPTH values indicating additional glands were analyzed.

RESULTS

The inclusion criteria were met by 1021 patients: 817 patients with SA (82.2 %), 99 patients with DA (10 %), and 78 with HA (7.9 %). The SA patients exhibited a 56.6 ± 4.9 % decline in IOPTH at 5 min compared with 21.3 ± 4.5 % of the DA patients and 22.5 ± 4.3 % of the HA patients (p < 0.01). Post hoc comparisons showed that the 5 min decrease in the SA group was significantly greater than in either the DA group or the HA group (p < 0.01). A 5 min percentage decline of 35 % best distinguished SA from multiglandular disease (85.3 vs. 24.9 %).

CONCLUSION

The data suggest that when IOPTH level does not drop by at least 35 % at 5 min after excision, the surgeon should consider further exploration rather than wait for additional levels.

Use of the gamma probe to identify multigland disease in primary hyperparathyroidism

AIM

The purpose of this study was to determine threshold gamma probe counts to distinguish single adenoma (SA) from multigland disease (MGD) during radioguided parathyroidectomy.

METHODS

A retrospective analysis of 1656 patients was performed. Ex vivo counts of the first excised gland were taken and recorded as a percentage of background counts.

RESULTS

69.4% of MGD patients had counts below the 50% threshold. The 50% threshold correctly grouped 72.8% of our cohort. Counts of more than 100% were accurate for grouping SA, with only 6.8% of patients with counts more than 100% having MGD.

CONCLUSIONS

The gamma probe can aid surgeons in deciding to continue neck exploration if MGD is suspected or wait for labs to confirm cure if SA is suspected.

Surgical management of the patient with primary hyperparathyroidism

Abstract: 

The successful surgical management of primary hyperparathyroidism requires a surgeon with a clear understanding of both the embryology and anatomy of the parathyroid glands. While the majority of patients may only have a single diseased gland, there is no 100% confirmation that can be attained in the preoperative period. For this reason, even when imaging is suggestive of a single diseased gland, additional intraoperative adjuncts should be used. Intraoperative parathyroid hormone monitoring is the most commonly used adjunct. When preoperative localization is not possible, or intraoperative parathyroid hormone levels fail to meet criteria for successful resection, the patient requires a four gland exploration. Cure is not confirmed until normocalcemia is documented for at least 6 months after surgery.

Is intraoperative parathyroid hormone testing in patients with renal insufficiency undergoing parathyroidectomy for primary hyperparathyroidism accurate?

BACKGROUND

Our aim was to determine whether chronic renal insufficiency (CRI) impacted intraoperative parathyroid hormone (ioPTH) monitoring during parathyroidectomy. We hypothesized that ioPTH monitoring in patients with CRI would show slower decline, but would still accurately predict cure.

METHODS

A retrospective review was conducted of patients with primary hyperparathyroidism who underwent curative single adenoma parathyroidectomy. The percentage of patients reaching 50% decline of ioPTH was compared between groups stratified by renal function.

RESULTS

Between 2000 and 2013, 950 patients met inclusion criteria. At 5 minutes, 66% of patients with CRI met curative criteria versus 77% of normal renal function patients (P = .001). At 10 minutes, 89% vs 92% met criteria (P = .073), and by 15 minutes, the gap narrowed to 95% vs 97% (P = .142), respectively.

CONCLUSIONS

Despite CRI patients with primary hyperparathyroidism having slower ioPTH decline after curative parathyroidectomy, 95% met ioPTH criteria by 15 minutes. Standard ioPTH criteria can be used with CRI patients.

Justified follow-up: a final intraoperative parathyroid hormone (ioPTH) Over 40 pg/mL is associated with an increased risk of persistence and recurrence in primary hyperparathyroidism

INTRODUCTION

After parathyroidectomy for sporadic primary hyperparathyroidism (PHPT), overall rates of persistence/recurrence are extremely low. A marker of increased risk for persistence/recurrence is needed. We hypothesized that final intraoperative parathyroid hormone (FioPTH) ≥40 pg/mL is indicative of increased risk for disease persistence/recurrence, and can be used to selectively determine the degree of follow-up.

METHOD

A retrospective review of PHPT patients undergoing parathyroidectomy with ioPTH monitoring was performed. An ioPTH decline of 50 % was the only criteria for operation termination. Patients were grouped based on FioPTH of <40, 40-59, and >60 pg/mL.

RESULTS

Between 2001 and 2012, 1,371 patients were included. Mean age was 61 ± 0.4 years, and 78°% were female. Overall persistence rate was 1.4°%, with a 2.9°% recurrence rate. Overall, 976 (71°%) patients had FioPTH < 40, 228 (16.6°%) had FioPTH 40-59, and 167 (12.2°%) had FioPTH ≥60. Mean follow-up was 21 ± 0.6 months. Patients with FioPTH <40 were younger, with lower preoperative serum calcium, PTH, and creatinine (all p ≤ 0.001). Patients with FioPTH <40 had the lowest persistence rate (0.2 %) versus patients with FioPTH 40-59 (3.5 %) or FioPTH ≥60 (5.4 %; p < 0.001). Recurrence rate was also lowest in patients with FioPTH <40 (1.3 vs. 5.9 vs. 8.2 %, respectively; p < 0.001). Disease-free status was greatest in patients with FioPTH <40 at 2 years (98.5 vs. 96.8 vs. 90.5 %, respectively) and 5 years (95.7 vs. 72.3 vs. 74.8 %, respectively; p < 0.01).

CONCLUSIONS

Patients with FioPTH < 40 pg/mL had lower rates of persistence and recurrence, than patients with FioPTH 40-59, or ≥60. Differences became more apparent after 2 years of follow-up. Patients with FioPTH ≥40 pg/mL warrant close and prolonged follow-up.

Parathyroid conditions in childhood

This review of parathyroid surgery in children will briefly discuss parathyroid gland embryology and anatomy before focusing on the pathophysiology, clinical presentation, and treatment of hyperparathyroidism in children. Hyperparathyroidism (HPT) is the overproduction of PTH and it is rare in children, with an incidence of 2-5 per 100,000. This rarity means that the principles of caring for children with parathyroid disease are largely extrapolated from the richer adult experience; however, the unique pediatric aspects of parathyroid problems and their surgical treatment, including presentation, imaging, operative approach, and complications, will be considered.

The role of the robotic-assisted transaxillary gasless approach for the removal of parathyroid adenomas

BACKGROUND

We sought to describe a robotic technique of transaxillary gasless parathyroidectomy for the management of primary hyperparathyroidism (PHPT) due to a parathyroid adenoma.

METHODS

All consecutive patients who underwent robotic parathyroidectomy for a parathyroid adenoma by a single surgeon were included. Data was obtained by a retrospective review of patients' medical charts.

RESULTS

Nine patients with confirmed PHPT underwent robotic parathyroidectomy. Curative resection was established in all patients with the aid of intraoperative parathyroid hormone monitoring. One patient required bilateral cervical exploration of multiglandular disease. There were no complications. Patients were followed up for a period exceeding 6 months without any evidence of persistent or recurrent hyperparathyroidism.

CONCLUSIONS

Our initial experience demonstrates that this technique is safe and effective for the treatment of PHPT. We believe that the use of robotic technology for endoscopic parathyroid surgeries could overcome the limitations of conventional techniques in the management of parathyroid lesions.

Parathyroid scintigraphy, histopathology correlation in patients with tropical pancreatitis and coexisting primary hyperparathyroidism

Purpose:

Tropical pancreatitis (TP) is a juvenile, non-alcoholic type of chronic pancreatitis and is highly prevalent in Kerala, India. Increasing prevalence of TP and its varied manifestations prompted us to undertake this retrospective analysis. We attempted to study the incidence of TP in patients with primary hyperparathyroidism (PHPT) and correlate with calcium levels, scintigraphy and histopathology findings.

Materials and Methods:

Records of 44 hypercalcemic patients with raised parathormone (PTH) were analyzed. Clinical, biochemical and imaging findings were noted to look for diabetes mellitus and pancreatitis. All patients underwent dual phase ^99m Technetium methoxy isobutyl isonitrile parathyroid scintigraphy in our department between January 2007 and 2010. Gamma probe assisted minimally invasive parathyroidectomy was performed. Histopathological correlation was obtained in all patients.

Results:

Our study shows 18% (8/44 patients) incidence of TP in patients with PHPT (compared to 7% reported in 1970's) in Kerala. Results show involvement of middle aged, non-alcoholic males. No direct association between severity of diabetes, pancreatitis and PHPT was noted in our series. Parathyroid adenoma was the most common underlying pathology. All TP patients’ clinical outcome improved post parathyroidectomy. TP patients with PHPT demonstrated adenomas, mainly composed of oxyphilic cells. Non pancreatitis group interestingly showed a varied picture of adenoma, hyperplasia with predominance of chief cells histologically.

Conclusion:

There is a 2.6 fold increase in the incidence of TP (18%) in patients with PHPT. Hypercalcemia may be the causative factor leading to TP in PHPT patients in our limited series. The data suggests a causal association between pancreatitis and PHPT. Patients presenting with either one or a combination of hypercalcemia, pancreatic dysfunction or raised PTH need to be thoroughly evaluated as their management is interlinked.

Multigland disease and slower decline in intraoperative PTH characterize mild primary hyperparathyroidism

BACKGROUND

Many patients with primary hyperparathyroidism (PHPT) present with less severe biochemical parameters. The purpose of this study was to compare the presentation, operative findings, and outcomes of these patients with "mild" PHPT to patients with "overt" disease.

METHODS

A retrospective review of a prospectively collected parathyroid database was performed to identify cases of PHPT undergoing an initial neck operation. Patients were classified as mild when either the preoperative calcium or PTH was within the normal limits. Comparisons were made with the Student's t test, Chi-squared test, or Wilcoxon rank-sum test where appropriate. Kaplan-Meier estimates were plotted for disease-free survival and compared by the log-rank test.

RESULTS

Of the 1,429 patients who met inclusion criteria, 1,049 were classified as overt and 388 (27.1 %) were mild. Within the mild group, 122 (31.4 %) presented with normocalcemic PHPT and 266 (68.6 %) had a normal PTH. The two groups had similar demographics and renal function. Interestingly, the mild group had more than double the rate of kidney stones (3.1 vs. 1.3 %, p = 0.02). The mild group was less likely to localize on sestamibi scan (62.4 vs. 78.7 %, p < 0.01). Intraoperatively, more mild patients exhibited multigland disease (34.3 vs. 14.1 %, p < 0.01). When examining intraoperative PTH (IoPTH) kinetics where single adenomas were excised, the IoPTH fell at a rate of 6.9 pg/min in mild patients compared with 11.5 pg/min in the overt group (p < 0.01). Accordingly, 62.2 % of patients in the overt group and 53.3 % in the mild group were cured at 5 min postexcision (p < 0.01). There was no difference in the rates of persistence or recurrence between the groups, and disease-free survival estimates were identical (p = 0.27).

CONCLUSIONS

Patients with mild PHPT were more likely to have multigland disease and a slower decline in IoPTH, but these patients can be successfully treated with surgery.

Radioguided parathyroidectomy effective in pediatric patients

BACKGROUND

Radioguided parathyroidectomy (RGP) has been shown to be effective in adult patients with hyperparathyroidism (HPT), but the utility of RGP in pediatric patients has not been systematically examined. It is not known if adult criteria for radioactive counts can accurately detect hyperfunctioning parathyroid glands in pediatric patients. The purpose of our study was to determine the utility of RGP in children with primary HPT.

MATERIALS AND METHODS

A retrospective review of our prospectively maintained single-institution database for patients who underwent a RGP for primary HPT identified 1694 adult and 19 pediatric patients aged 19 y or younger. From the adult population, we selected a control group matched three to one for gland weight and gender and compared pre- and postoperative laboratory values, surgical findings, pathology, and radioguidance values between the control and the pediatric groups.

RESULTS

Excised glands from pediatric patients were smaller than those in the total adult population (437 ± 60 mg versus 718 ± 31 mg, P = 0.0004). When controlled for gland weight, ex vivo counts as a percentage of background were lower in the pediatric group (51% ± 5% versus 91% ± 11%, P = 0.04). However, ex vivo radionuclide counts >20% of the background were found in 100% of pediatric patients and 95% of the adult-matched control group.

CONCLUSIONS

All pediatric patients met the adult detection criteria for parathyroid tissue removal when a RGP was performed, and 100% cure was achieved. We conclude that RGP is a useful treatment option for pediatric patients with primary HPT.

Incidence and localization of ectopic parathyroid adenomas in previously unexplored patients

BACKGROUND

Parathyroidectomy has a success rate of >95 % for cure of primary hyperparathyroidism. In about 6-16 % of cases, one or more hyperfunctioning parathyroid gland(s) are found in an ectopic location. Accurate preoperative imaging can aid in detecting these ectopically located glands and allow a focused surgical approach with an even higher success rate. The objective of this study was to assess the utility of ultrasonography (US) and technetium-99m-sestamibi (MIBI) scans in locating ectopic parathyroid glands in previously unexplored patients who presented with primary hyperparathyroidism.

METHODS

We analyzed a total of 1,562 patients who underwent surgery for hyperparathyroidism at our institution from 2000 to 2010. Ectopic parathyroid adenomas were identified in 346 of the patients (22 %). Of the 346 patients, we excluded 144 who underwent reoperations, had four-gland hyperplasia or were missing imaging details. We carefully reviewed the data, including demographics, laboratory values, preoperative localizing imaging details, and operative findings. Preoperative US and MIBI results were compared to the intraoperative findings.

RESULTS

We analyzed 202 patients with ectopic glands for accuracy of preoperative localization. Of these 202 patients, a single adenoma was the most common (89 %) followed by double adenoma (11 %). The ectopic parathyroid glands were predominantly located in the thymus (38 %) followed by 31 % in the retroesophageal region; 18 % were intrathyroidal. Preoperative MIBI scans had a sensitivity of 89 % (161/197), whereas US had a sensitivity of 59 % (35/63) for detecting ectopic glands. Overall, both imaging modalities had a positive predictive value of 90 %, with MIBI correctly predicting ectopic glands best in the thymus, mediastinum, or the retroesophageal space, and US was most accurate at detecting intrathyroidal glands.

CONCLUSIONS

Based on the data available at our institution, MIBI has a higher sensitivity than US in correctly localizing ectopic parathyroid adenomas, but the accuracy of detection varies based on location. Both imaging techniques have a high PPV for detecting an ectopic gland. Therefore, imaging with MIBI and US can be complementary, and positive localization of an ectopic gland with either modality is highly accurate and can facilitate a more focused surgical approach.

Creation of a "Wisconsin index" nomogram to predict the likelihood of additional hyperfunctioning parathyroid glands during parathyroidectomy

OBJECTIVE

The aim of our study was to create a preoperative "index" that could predict the likelihood of additional hyperfunctioning parathyroid glands and let the surgeon determine whether to wait for the intraoperative parathyroid hormone (ioPTH) or to explore further.

BACKGROUND

During parathyroidectomy for primary hyperparathyroidism (PHPT), discovering a minimally "enlarged" parathyroid gland creates a dilemma for the surgeon regarding the need for further exploration. Although ioPTH testing can potentially solve this problem after a 20- to 30-minute period, several surgeons recognize that further operative exploration may be more effective.

METHODS

We analyzed a prospective database of 1235 consecutive patients who underwent parathyroidectomy for PHPT at our institution between March 2001 and August 2010. The Wisconsin Index (WIN) was defined as the multiplication of preoperative serum calcium by preoperative parathyroid hormone (PTH). Patients were divided into 3 WIN categories: low (<800), medium (801-1600), and high (>1600). The utility of the WIN was then validated on a subsequent cohort of 216 patients.

RESULTS

The median age of the patients was 61 years (range, 10-91), and 77% of the patients were female. The mean preoperative calcium and PTH levels were 11.0 ± 0 mg/dL and 127 ± 3 pg/mL, respectively. The mean WIN for the entire cohort was 1461 ± 38 and highly correlated with gland weight (P < 0.000001). A single adenoma was identified in 1000 patients (81%), double adenoma in 100 patients (8%), and hyperplasia in 135 patients (11%). The mean gland weights for the 3 WIN catagories were low = 370 ± 33 mg, medium = 532 ± 39 mg, and high = 985 ± 28 mg, respectively (P < 0.000001). A WIN nomogram, consisting of the combination of WIN and parathyroid gland weight, accurately predicted the likelihood of additional hyperfunctioning parathyroid glands. For example, for a WIN of less than 800 and a gland weight of 500 mg, there is a 9% chance for additional hyperfunctioning parathyroid glands based on the WIN nomogram. In contrast, for the same gland weight, if the WIN is 801 to 1600, these chances increase to 28%, and if the WIN is more than 1600, the chance of multigland disease is 61%. Comparison between the predicted chances for another gland with the actual chance in the validation cohort identified an R(2) value of 0.96.

CONCLUSIONS

The WIN nomogram predicts the likelihood of additional hyperfunctioning parathyroid glands during parathyroidectomy. This simple intraoperative tool may be used to guide the decision of whether to wait for ioPTH results or to proceed with further neck exploration.

Significance of rebounding parathyroid hormone levels during parathyroidectomy

BACKGROUND

Using minimally invasive parathyroidectomy (MIP), most surgeons require a 50% decline in intraoperative parathyroid hormone (IoPTH) to determine cure, but the significance of IoPTH kinetics occurring after this drop remains unknown. The aim of this study was to determine the impact of IoPTH levels that first meet criteria for cure, but then increase again, or rebound, between 10 and 15 min postexcision.

METHODS

We conducted a retrospective review of patients undergoing initial parathyroidectomy for primary hyperparathyroidism at our institution from 2001 to 2011. Rebound IoPTH was defined as an increase in parathyroid hormone ≥5 pg/mL after achieving the 50% drop required for cure. Comparisons were evaluated with the Student t-test, chi-square test, or Fisher exact test where appropriate.

RESULTS

Of the 1386 patients who met selection criteria, 86 (6.2%) patients exhibited rebound IoPTH. The mean magnitude of rebound was 13.8 ± 3.6 pg/mL. Compared with those not displaying rebound, more patients with rebound IoPTH were treated with open parathyroidectomy rather than MIP (10.8% versus 4.5%, P < 0.01). The recurrence rate among those with rebound IoPTH was more than double that of the patients without rebound IoPTH (5.8% versus 2.2%, P = 0.03). Magnitude of rebound, however, did not correlate with recurrence. The rate of persistent disease was not different between those with and without rebound IoPTH. Rebound was a much better indicator of recurrence than patients whose final IoPTH levels were not within the normal range.

CONCLUSIONS

Rebound IoPTH is more common in patients who develop recurrent hyperparathyroidism. Therefore, surgeons should closely monitor patients with rebound IoPTH for disease recurrence.

Parathyroidectomies Using Intraoperative Parathormone Monitoring: When Should We Stop Measuring Intraoperative Parathormone Levels?

Intraoperative parathyroid hormone monitoring (IOPM), in use for the last 15 years, has facilitated focused parathyroidectomy. We undertook this study to determine if a drop in IOPT hormone levels below 50 per cent of baseline were sufficient to terminate the procedure. We conducted a retrospective chart review (January 2007 to September 2010) of 104 patients who underwent initial parathyroidectomies with IOPM by general surgeons for primary hyperparathyroidism. Patients were followed up for serum calcium levels (range, 6 to 48 months). The number of specimens excised was significantly decreased when IOPT hormone levels dropped to greater than 50 per cent and came within the normal range earlier. Moreover, for single-gland parathyroid adenomas, once the parathyroid hormone values dropped to less than 50 per cent in the 5-minute sample, they continued to decrease in the subsequent samples. In 23 cases requiring further exploration, the parathyroid hormone values had already decreased to greater than 50 per cent in 14 cases but had not normalized (reference range, 8 to 74), leading to additional exploration. However, subsequent pathologic analysis showed that the initial gland removed was the adenoma in all these cases. A drop in the initial 5-minute parathyroid hormone value to less than 50 per cent of the baseline should serve as sufficient evidence to terminate the procedure. This would translate into significant laboratory and personnel cost savings over time. However, this should be carefully correlated with preoperative ultrasound/sestamibi findings.

Does the final intraoperative PTH level really have to fall into the normal range to signify cure?

BACKGROUND

Intraoperative parathyroid hormone (IOPTH) helps shorten the duration of surgery and increase the likelihood of surgical cure. Although general consensus agrees that the IOPTH should fall by 50%, there is much debate as to whether the IOPTH needs to fall into the normal range.

METHODS

We retrospectively reviewed a prospective database of patients undergoing surgery for treatment of primary hyperparathyroidism. We included all patients with an IOPTH that fell by >50% by 10 or 15 min, but that did not fall into the normal range (parathyroid hormone remained ≥ 60 pg/ml). We excluded patients who had undergone prior neck surgery or had known multiple endocrine neoplasia 1 or 2.

RESULTS

A total of 1,231 patients underwent a parathyroidectomy, 155 of whom met the study's inclusion/exclusion criteria (12.6%). A total of 117 patients had an IOPTH fall by 50% by 10 min, and 38 patients' IOPTH fell by 50% by 15 min. Overall surgical cure rate was 98.7%. One patient from the 10-minute group and one patient from the 15-minute group had persistent disease on follow-up. One patient in the 15-minute group had recurrent disease. With a mean ± SEM 18.1 ± 2.1 months' follow-up, the recurrence rate in this cohort was 0.6%. The average calcium at last follow-up was 9.4 ± 0.0 mg/dl.

CONCLUSIONS

Allowing the IOPTH to fall by 50% by 15 min, regardless of whether the IOPTH falls into the normal range, results in a high success rate when performed by experienced surgeons. This helps reduce intraoperative time used waiting for additional parathyroid hormone levels and the risks associated with unnecessary bilateral neck exploration.

The necessity and reliability of intraoperative parathyroid hormone (PTH) testing in patients with mild hyperparathyroidism and PTH levels in the normal range

BACKGROUND

Intraoperative parathyroid hormone (IoPTH) testing is useful in the management of hyperparathyroidism. The successful removal of hypersecreting parathyroids is indicated by a decrease in PTH levels >50% within 15 min. A subset of patients with mild hyperparathyroidism will actually have starting PTH levels in the normal range. We sought to determine if IoPTH testing is necessary in these patients and if the 50% rule delineating surgical cure is reliable.

METHODS

A retrospective review was performed on all patients who underwent parathyroidectomy for hyperparathyroidism at a single institution from 3/2001 to 8/2008.

RESULTS

Of the 1,001 patients, 142 (14%) had mild hyperparathyroidism and normal baseline PTH levels (<65 pg/ml). Their mean PTH was 59 ± 1 pg/ml. During surgery, 105 (74%) had a >50% decline in PTH levels after resection of hyperfunctioning parathyroid glands, and their operations were terminated. In contrast, 37 (26%) patients did not have a >50% decline in PTH levels leading to further surgical exploration. In these 37 patients, the PTH levels fell by >50% after the removal of the additional glands in 25 patients (17.6%) and dropped after 20 min in 7 patients (4.9%). In 5 patients (3.5%) the IoPTH did not drop. Of the 142 total patients, 91 had single adenomas and 51 patients had multi-gland disease. All patients (100%) were cured (normal serum calcium after 6 months).

CONCLUSIONS

Intraoperative PTH testing plays an important role in the operative management in 14% of patients with mild hyperparathyroidism. Importantly, a 50% decline in IoPTH level within 15 min of parathyroidectomy is 96.5% reliable in predicting cure in these patients with PTH starting in the normal range.

Influence of surgical volume on operative failures for hyperparathyroidism

Hyperparathyroidism is a disease that is often seen in the United States. Patients may present with a wide variety of symptoms affecting multiple organs, but frequently, they are found to be hyperparathyroid on a routine blood examination. Although these patients may be asymptomatic, new consensus guidelines exist for when they should undergo surgery, and several studies have shown multiple benefits from operative intervention. Surgical cure rates can be greater than 95%, but if the initial surgery is unsuccessful, the cure rate becomes 80%. In the hands of experienced surgeons, both initial cure rates and those for reoperations are much higher, illustrating that the surgical volume does affect failure in parathyroid surgery.

Intraoperative adjuncts for parathyroid surgery

In recent years, parathyroid surgery has evolved from traditional bilateral neck exploration to minimal invasive parathyroidectomy. This trend became possible due to preoperative localization imaging that guides the surgeon in the search for a parathyroid adenoma. Intraoperative adjuncts are complementary to preoperative localization and assist in localizing parathyroid glands, confirming parathyroid tissue and establishing a cure. Institutions and surgeons utilize different intraoperative adjuncts in different protocols with varying results. The purpose of this article is to review the available intraoperative adjuncts to parathyroid surgery and critically evaluate their utility, accuracy and their added value to the surgeon.