Intraoperative Parathyroid Hormone Decrease Research Articles

A >50% Intraoperative Parathyroid Hormone Decrease Into Normal Reference Range Predicts Complete Excision of Malignancy in Patients With Parathyroid Carcinoma

IntroductionThe mainstay of successful treatment for parathyroid carcinoma remains complete surgical excision. Although intraoperative parathyroid hormone (ioPTH) monitoring is a useful adjunct during parathyroidectomy for benign primary hyperparathyroidism, its utility for parathyroid carcinoma remains unclear. MethodsA retrospective review of 796 patients who underwent parathyroidectomy with ioPTH monitoring for primary hyperparathyroidism revealed 13 patients with parathyroid carcinoma on final pathology from two academic institutions. A systematic review yielded 5 additional parathyroid carcinoma patients. Complete excision of malignancy, or operative success (eucalcemia ≥6 mo. after parathyroidectomy); operative failure (persistent hypercalcemia <6 mo. after parathyroidectomy); and perioperative complications were evaluated. Comparison of the >50% ioPTH decrease alone to >50% ioPTH decrease into normal reference range was analyzed using Chi-squared, Kolmogorov–Smirnov, Kruskal–Wallis tests. ResultsAll 18 parathyroid carcinoma patients achieved a >50% ioPTH decrease, and 14 patients also had a final ioPTH level decrease into normal reference range. 93% of patients who met normal parathyroid hormone reference range had operative success, whereas only two of the four (50%) patients with parathyroid carcinoma with a >50% ioPTH decrease alone demonstrated operative success. ConclusionsParathyroidectomy guided by a >50% ioPTH decrease into normal reference range may better predict complete excision of malignant tissue in patients with parathyroid carcinoma compared to >50% ioPTH decrease alone. IoPTH monitoring should be used in conjunction with clinical judgment and complete en bloc resection for optimal treatment and success.

Parathyroidectomy for primary hyperparathyroidism: A retrospective analysis of localization, surgical characteristics, and treatment outcomes

ObjectiveTo evaluate parathyroidectomy for primary hyperparathyroidism (PHPT) regarding localization, surgical characteristics, and treatment outcomes. MethodsSeventy-eight patients who underwent parathyroidectomy for PHPT were retrospectively reviewed. The results were analyzed according to intraoperative localization technique (IOLT), intraoperative parathyroid hormone (IOPTH) monitoring, and intraoperative nerve monitoring (IONM). The localization accuracy of ultrasonography (US), computed tomography (CT), and single-photon emission computed tomography (SPECT)-CT with sestamibi Tc99m was evaluated. ResultsParathyroidectomy was successfully completed in all 78 patients, achieving 100% surgical cure. For 60 patients with IOPTH monitoring, 10-min IOPTH decreased >50% from baseline in 57 (95.0%), and they achieved surgical cure. In the remaining three (5.0%) patients with ≤50% decrease in 10-min IOPTH, 20-min IOPTH decreased >50% from baseline in two (3.3%) patients, achieving surgical cure without additional neck exploration. There were no differences in surgical cure and complications as a function of IOLT use or IOPTH monitoring. Operating time was significantly shorter with IOLT and IOPTH monitoring than without (IOLT: 70.9 min vs. 88.0 min, p = 0.013; IOPTH: 74.9 min vs. 91.9 min, p = 0.037). All 78 patients had adenoma including one patient with a double adenoma. Vocal cord paralysis was not observed in our series, regardless of IONM. US, CT, and SPECT-CT localized the pathological parathyroid gland accurately in 88.1%, 85.5%, and 86.8% of patients, respectively (p = 0.894). ConclusionThe surgical outcomes of parathyroidectomy for PHPT were excellent regardless of IOLT and IOPTH monitoring. However, these techniques can maximize the performance of parathyroid surgery by reducing operating time and rescuing challenging cases.

Critical analysis of the intraoperative parathyroid hormone decrease during parathyroidectomy for secondary and tertiary hyperparathyroidism

BackgroundThis study aims to determine whether intraoperative parathyroid hormone monitoring helps to predict early surgical outcomes in patients with renal hyperparathyroidism and evaluate the impact on decision making during surgery. MethodsA prospective study was conducted. Serial samples of the intraoperative parathyroid hormone were collected; 2 of these were taken before the excision, and 2 were taken after the planned parathyroid resection (10 minutes and 15 minutes). We tested the criterion of an intraoperative parathyroid hormone percentage decay ≥80% of the highest value of the basal samples as a predictor of success. ResultsOf the 228 patients, parathyroidectomy achieved success in 92.1%. In patients with secondary hyperparathyroidism, the failure group showed a tendency to stabilize or even increase the intraoperative parathyroid hormone values from the 10-minute measure (577 pg/mL) to the 15-minute measure (535 pg/mL) (P = .903). Conversely, intraoperative parathyroid hormone continued to drop in those with a successful outcome: 245 pg/mL (10 minutes) and 206 pg/mL (15 minutes) (P < .001). The failure group had a significantly lower percentage decay (P < .001) from baseline when compared with the success group. The intraoperative parathyroid hormone influenced the surgical management in up to 7% of the cases. The intraoperative parathyroid hormone dosage method showed an accuracy of 86%, a sensitivity of 88%, and specificity of 67%. ConclusionIn patients with renal hyperparathyroidism undergoing parathyroidectomy, the use of intraoperative parathyroid hormone may help to predict an early therapeutic outcome with high sensitivity and accuracy by indicating the operation's success when there is an 80% reduction of baseline intraoperative parathyroid hormone 15 minutes after removal of the enlarged glands, an associated continuous decrease in serum intraoperative parathyroid hormone levels between 10 and 15 minutes, and achievement of plasma target values <500 pg/mL.

Intraoperative parathyroid hormone (IOPTH) assay might be better than the second-generation assay in parathyroidectomy for primary hyperparathyroidism

BackgroundIt is unclear whether the third-generation intraoperative parathyroid hormone assay can improve surgical outcomes over second-generation assay in primary hyperparathyroidism. We aimed to compare the rate of decrease and diagnostic accuracy between the two assays after parathyroid adenoma excision. MethodsConsecutive patients undergoing parathyroidectomy with intraoperative parathyroid hormone were analyzed. Blood was drawn before and 10 minutes and 20 minutes after excision of the adenoma. The same blood sample was run simultaneously in the second-generation assays (Elecsys PTH STAT) and third-generation assays (Elecsys 1–84 PTH). Biochemical cure meant >50% intraoperative parathyroid hormone decrease at 10 minutes. Cure meant normocalcemia 6 months after operation. ResultsRelative to the second-generation assay, the value of the intraoperative parathyroid hormone level was less in the third-generation assay before excision (P < .001), at 10 minutes (P < .001), and at 20 minutes (P < .001). The intraoperative parathyroid hormone rate of decrease and the proportion of normalized post-excision intraoperative parathyroid hormone were greater in the third-generation assay (P < .001), but the prediction accuracy appeared similar between the 2 (91.5% vs 91.0%). Patients with worse renal function (estimated glomerular filtration rate <80mL/min/1.73m2) had a slower intraoperative parathyroid hormone decrease in the second-generation but not in the third-generation assay. ConclusionDespite comparable accuracy between the two generations of assay, the third-generation assay might be better than the second-generation assay because of the more rapid decrease in the intraoperative parathyroid hormone and a greater percentage of normalized intraoperative parathyroid hormone, regardless of baseline renal function.

Single Gland, Ectopic Location: Adenomas are Common Causes of Primary Hyperparathyroidism in Children and Adolescents.

Primary hyperparathyroidism (PHPT) in children and adolescents is uncommon. Data-driven guidelines for management in pediatric patients are limited. We performed a retrospective cohort analysis of all patients (1997-2017) with PHPT ≤ 21years of age who underwent parathyroidectomy at three institutions. Clinical and demographic variables were analyzed. Primary operative outcome was cure (normocalcemia > 6months after surgery); secondary outcome was operative success (intraoperative parathyroid hormone decrease of ≥ 50%). We identified 86 patients with a median age of 17years (IQR: 14, 19); 64% (n = 55) were female. The mean preoperative serum calcium was 11.7mg/dL, median parathyroid hormone (PTH) was 110pg/mL, and median urine calcium was 4.1mg/kg/24h. Preoperatively, sestamibi scan localized in 41/71 patients (58%); neck ultrasound localized in 19/44 (43%). The most common pathology at surgery was a single ectopic parathyroid adenoma in 71% (n = 61). A high incidence of ectopic adenomas (25%, n = 22) was observed, most commonly intrathymic (n = 13), followed by tracheoesophageal groove (n = 5), carotid sheath (n = 2), and intrathyroidal (n = 2). Of 56 patients with retrievable data > 6months postoperatively, cure was achieved in 55 of 56 patients (98%). One patient who presented to us with parathyromatosis require subsequent reoperation. In this multi-institutional series of PHPT in children and adolescents, the majority were sporadic PHPT and were due to a single adenoma. We observed a high incidence of ectopic parathyroid adenomas, most commonly intrathymic. Given the high risk for ectopic adenoma in pediatric patients, parathyroid surgery in children and adolescents should be performed by experienced surgeons.

Intraoperative Parathyroid Hormone Monitoring in Parathyroidectomy for Tertiary Hyperparathyroidism

BackgroundTertiary hyperparathyroidism (THPT) is characterized by hypercalcemia and hyperparathyroidism after renal allograft. Limited data exist regarding the use of intraoperative parathyroid hormone (IOPTH) for THPT. We examined our series of parathyroidectomies performed for THPT to determine clinical outcomes with respect to IOPTH. Materials and methodsPatients who underwent parathyroidectomy for THPT (1999-2017) were identified for inclusion. Retrospective chart review was performed. Cure was defined as eucalcemia ≥6 mo after surgery. Statistical analysis was performed. ResultsOf 41 patients included in the study, 41% (n = 17) were female. The median duration of dialysis before renal allograft was 34 mo (interquartile interval [IQI]:6-60). Preoperatively, the median calcium level was 10.4 mg/dL (IQI:10.0-11.2), median parathyroid hormone was 172 pg/mL (IQI:104-293), and renal function was minimally abnormal with median glomerular filtration rate 58 mL/min/1.73 m2 (IQI:49-71). At surgery, the median final IOPTH was 40 pg/mL (IQI:29-73), and median decrease in IOPTH was 78% (IQI:72-87), with 88% (n = 36) of patients demonstrating >50% decrease. Median calcium level ≥6 mo after surgery was 9.4 mg/dL (IQI:8.8-9.7), and only one patient had recurrent hypercalcemia. Failure to achieve >50% decrease in IOPTH was not significantly associated with recurrent hypercalcemia (P = 1.000). With a median follow-up time of 41 mo (IQI:25-70), only three patients had graft failure. The positive predictive value of IOPTH for cure was 89% (95% confidence interval: 0.752-0.971), with 0% negative predictive value and 87% accuracy (95% confidence interval: 0.726-0.957). ConclusionsSubtotal parathyroidectomy is a successful operation with durable cure of THPT. IOPTH fails to predict long-term cure in THPT despite minimally abnormal renal function.

Pre-Operative Localization of Parathyroid Adenoma: Performance of 4D Mri Parathyroid Protocol

Objective: Accurate pre-operative image localization is critical in the selection of minimally invasive parathyroidectomy as a surgical treatment approach in patients with primary hyperparathyroidism (PHPT). Sestamibi scan, ultrasound, computed tomography, and conventional magnetic resonance imaging (MRI) has varying accuracy in localizing parathyroid adenoma (PTA). Our group has previously shown that four-dimensional (4D) MRI is more accurate than conventional imaging in identifying single adenomas. In this study, we set out to determine if it is possible to accurately localize the quadrant of the adenoma using 4D MRI. Methods: We analyzed and matched the quadrants of PTA identified by pre-operative 4D-MRI with the operative findings during parathyroidectomy for PHPT at our institution during the study period. All resections were confirmed to be successful with an adequate decrease in intraoperative parathyroid hormone as defined by the Miami criterion. Results: A total of 26 patients with PHPT underwent pre-operative localization with the 4D MRI parathyroid protocol. Fourteen patients had true single-gland adenoma (SGA) and 12 patients had multi-gland disease (MGD). 4D MRI accurately identified all the SGA. Using this method, we were also able to localize the adenoma in the correct quadrant in 14 of the 18 patients with SGA. All 3 double adenomas were accurately identified using 4D MRI; however, MGD was only accurately identified 67% of the time. The 4D MRI had an overall 85% accuracy in distinguishing SGA from MGD. Conclusion: 4D MRI accurately identified single and double adenomas in their respective quadrants. However, accuracy was lower with MGD. Abbreviations: BNE = bilateral neck exploration; CT = computed tomography; IOPTH = intra-operative parathyroid hormone; MGD = multi-gland disease; MIBI = sestamibi; MIP = minimally invasive parathyroidectomy; MRI = magnetic resonance imaging; PHPT = primary hyperparathyroidism; PTA = parathyroid adenoma; PTH = parathyroid hormone; SGA = single-gland adenoma; SPECT = single photon emission computed tomography; 4D = four-dimensional.

Primary Hyperparathyroidism: Redefining Cure

Primary hyperparathyroidism is the most common cause of hypercalcemia. Follow-up can be resource-intensive and costly. The aim of this study was to determine if there is a subset of patients who can be defined cured earlier than six months. This was a retrospective study of patients who underwent parathyroidectomy between January 2012 and March 2014. Patients with a history of multiple endocrine neoplasia syndrome, and secondary or tertiary hyperparathyroidism were excluded. Patients with normal preoperative calcium and parathyroid hormone (PTH) and those without six months follow-up were excluded. Patients were divided into two groups: cured and not cured. Data analysis was performed between the two groups. A total of 509 patients were screened, and 214 met our inclusion criteria: 202 in the cured category and 12 in the not cured category (94% cure rate). There was no significant difference between age, gland weight, or preoperative PTH. There was a statistically significant difference between final intraoperative PTH (IOPTH) (37 vs 55, P = 0.008) and per cent PTH decrease (69 vs 43%, P < 0.0001). There was a significant difference between intraoperative cure rate (P < 0.0006), imaging concordance (P = 0.0115), and solitary versus multiglandular disease (P = 0.0151). Subgroup analysis in patients with concordant imaging, solitary parathyroid adenoma, and IOPTH decrease by 50 per cent to normal or near-normal correlated with a six-month cure rate of 97 per cent. Patients with primary hyperparathyroidism with concordant imaging, single-adenoma pathology, and IOPTH decrease by 50 per cent to normal or near-normal levels (15-65 pg/mL) can be considered cured and may need less frequent follow-up.

Factors Influencing Time to Decrease in Intraoperative Parathyroid Hormone (ioPTH) Levels in Patients Undergoing Focused Parathyroidectomy (FP)

The aim of this study was to evaluate potential factors affecting the time period in which a 50 per cent parathyroid hormone (PTH) drop is observed. Eight-seven patients undergoing focused parathyroidectomy between 2011 and 2015, whose PTH values dropped to within normal range, were grouped according to whether they required > or ≤15 minutes after gland excision to achieve a 50 per cent PTH. Groups were compared according to preoperative PTH, calcium, age, glomerular filtration rate, and adenoma weight. Lower preoperative and preincision PTH levels were associated with requiring >15 minutes to achieve a >50 per cent drop in ioPTH. Time to >50 per cent ioPTH drop did not affect cure rates at one year, though a >15 minutes requirement was associated with higher serum calcium levels (P = 0.015). Lower baseline PTH and preincision PTH levels are significantly associated with a >15 minutes postexcision time to achieve a >50 per cent drop in ioPTH. Future analyses are warranted to determine whether a longer postexcision time threshold before proceeding with four-gland exploration is warranted in patients with primary hyperparathyroidism and mildly elevated preoperative PTH.

Characterizing the operative findings and utility of intraoperative parathyroid hormone (IOPTH) monitoring in patients with normal baseline IOPTH and normohormonal primary hyperparathyroidism

During parathyroidectomy with intraoperative parathyroid hormone monitoring, the successful removal of a hypersecreting gland(s) resulting in normocalcemia is indicated by a >50% decrease in intraoperative parathyroid hormone level, typically into the normal range. Some patients, however, will have baseline parathyroid hormone levels within the normal range. We sought to determine the utility of intraoperative parathyroid hormone testing in these patients. We retrospectively studied all patients who underwent parathyroidectomy for primary hyperparathyroidism at our institution over a 10-year period. Overall, 317 (17%) patients had parathyroid hormone within the normal range at the onset of operation (baseline intraoperative parathyroid hormone), and 1,544 (83%) had classic primary hyperparathyroidism. The intraoperative parathyroid hormone degradation was slower in normal baseline intraoperative parathyroid hormone patients than classic primary hyperparathyroidism patients, though this did not reach statistical significance (P < .254). A >50% intraoperative parathyroid hormone decrease predicted cure in 98.7% of normal baseline patients and 98.8% of classic primary hyperparathyroidism patients (P=.810). Normal baseline patients had a lesser cure rate the longer it took to achieve a 50% decrease intraoperatively; however, the cure rate was constant at any time point the 50% decrease occurred in patients with classic primary hyperparathyroidism (P<.05). The 50% rule delineating operative cure can be applied with equal confidence to patients with normal range, baseline intraoperative parathyroid hormone. Moreover, the time at which the 50% drop is achieved impacts operative success rates in these patients.

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

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. 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. 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). 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.

Focused parathyroidectomy with intraoperative parathyroid hormone monitoring in patients with lithium-associated primary hyperparathyroidism

Lithium-associated hyperparathyroidism has been attributed to multigland hyperplasia requiring bilateral exploration and subtotal parathyroidectomy. Recent studies suggest that some patients may have single gland disease and be eligible for minimally invasive parathyroidectomy. We performed a retrospective review of a prospective, single institution parathyroid database of 1,010 patients who underwent parathyroidectomy between December 1999 and October 2010. Nineteen patients with a history of lithium therapy and sporadic hyperparathyroidism were identified. Median age was 50 years (16-68); median duration of therapy was 19 years (1-37); 11 (58%) were on active therapy with lithium for multiple reasons. Preoperative median serum calcium was 10.9 mg/dL (10.0-12.3), median parathyroid hormone was 111 pg/mL (60-186). A total of 18 patients underwent preoperative imaging. Of 12 patients with single-site localization, 6 (50%) underwent a minimally invasive parathyroidectomy, 2 (17%) underwent unilateral explorations, 1 (8%) underwent bilateral exploration, and 3 (25%) had concomitant thyroidectomies. Six patients did not localize and underwent bilateral exploration for multigland disease. One patient without preoperative imaging had single-gland disease. In all operations surgeons used intraoperative parathyroid hormone (IOPTH) monitoring and met intraoperative criteria. Median IOPTH decrease was 74% (54-86) in single-gland disease and 85% (76-95) in multigland disease. Median abnormal gland weight was 590 mg (134-6,750) in single-gland disease and 296 mg (145-2,170) in multigland disease. All patients were normocalcemic at a median follow-up of 19 months (2-118). Of 19 patients with lithium exposure, 6 (32%) had multigland disease. However, of the 13 (68%) patients with single gland disease, all 12 who had preoperative imaging had single-site localization. If localization suggests single gland disease, minimally invasive parathyroidectomy with IOPTH monitoring can be successfully performed.

The impact of vitamin D status and tumor size on the intraoperative parathyroid hormone dynamics in patients with symptomatic primary hyperparathyroidism

The intraoperative parathyroid hormone (IOPTH) monitoring is a useful adjunct for predicting whether a cure has been obtained during parathyroidectomy. We studied the influence of vitamin D status and parathyroid tumor weight on the IOPTH dynamics for predicting a cure in patients with symptomatic primary hyperparathyroidism. Fifty-nine primary hyperparathyroidism patients with a single adenoma underwent curative surgery. Patients were grouped according to their serum 25-hydroxy vitamin D levels (deficient, insufficient and sufficient) and tumor weights (small, large and giant). The IOPTH results in patient groups were compared, and the percentage of the IOPTH decrease was examined for a correlation with the serum 25-hydroxy vitamin D level and tumor weight. The sensitivity, specificity and overall accuracy of IOPTH in predicting a cure of hyperparathyroidism were 94.8, 100 and 93.2%, respectively. The percentage decrease in the IOTPH was significantly higher in the vitamin D deficient, compared to the vitamin D sufficient patients (p = 0.012); and in the patients with larger tumors, compared to those with smaller parathyroid tumors (p = 0.02). A statistically significant correlation was found between the percentage decrease in the IOPTH at 10 min post-tumor excision and the serum 25-hydroxy vitamin D level (p = 0.037), but not with the tumor weight (p = 0.208). The IOPTH can accurately predict a cure in patients with severe primary hyperparathyroidism. The percentage of decrease in the IOPTH is steeper in patients with lower serum 25-hydroxy vitamin D levels and larger parathyroid tumors.

Minimally invasive parathyroidectomy for primary hyperthyroidism guided by intra-operative parathyroid hormone monitoring

s / International Journal of Surgery 10 (2012) S1–S52 S32 ABSTRACTS course of IA mean free T4 was 30 pmol/L and 11.4 pmol/L respectively (range: 9.4 to 22.7 pmol/L). There were no adverse effects to IA. Therewere no complications following surgery. Conclusions: Iopanoic acid is safe and effective in rapidly controlling thyrotoxicosis prior to total thyroidectomy. 0623: SESTA-MIBI SCANS, CAN THEY PREDICT INTRATHYROID PARATHYROID ADENOMA? Rachel French, R.K. Maitra, Vijay Kurup. North Tees University Hospital, Stockton-on-Tees, UK Aim: To evaluate the role of sesta-mibi scans in predicting intrathyroidal parathyroid adenoma in primary hyperparathyroidism. Method: Retrospective analysis of parathyroidectomies performed in a distric general hospital during the last 6 years(2005-11). Sesta-mibi scans were performed pre-operatively in all patients with primary hyperparathyroidism. Where no adenoma was identified during exploration of neck, a hemithyroidectomy was performed on the side suggested by sestamibi scan. Results: 78 patients had exploration of neck, 82% female, 18% male, with a mean age 62 years. Sestamibi was positive in 60 patients and 54 had parathyroid adenoma identified on exploration. 6 patients after a failed neck exploration underwent hemithyroidectomy . Histology revealed intrathyroidal parathyroid adenoma in 5 patients(83%) . Out of 18 patients with negative scans 14 had an adenoma removed. Sestamibi scans had a sensitivity of 81% and positive predictive value of 98.3%. Conclusion: Sestamibi scan helped to identify 5patients with intrathyroidal parathyroid adenoma when neck exploration was negative. When no adenoma is visible on exploration a hemithyroidectomy at the side suggested by the scan is justified. 0681: MINIMALLY INVASIVE PARATHYROIDECTOMY FOR PRIMARY HYPERTHYROIDISM GUIDED BY INTRA-OPERATIVE PARATHYROID HORMONE MONITORING Alison Lyon , O.O. Komolafe , Christopher Wilson . University of Sydney, Sydney, Australia; Western Infirmary, Glasgow, UK Aim: Intra-operative parathyroid hormone (PTH) levels can demonstrate successful removal of a parathyroid adenoma during minimally invasive parathyroidectomy. However, this technique remains controversial due to variations in blood sampling and excision criteria. In this study, we explored the success rate of our technique. Methods: A consecutive series of 92 patients with histologically confirmed primary hyperparathyroidism was analysed retrospectively. All were treated with a minimally invasive technique. Serum PTH levels were checked prior to gland removal and twenty minutes after gland removal to confirm a decrease of greater than 50%, which was considered to indicate a curative procedure. Results: The median pre-operative PTH level was 14.35ng/L (interquartile range (IQR) 10.7-20.3). The two week post operative median level was 5.4ng/L (IQR 3.4-7) and median adjusted calcium level was 2.39mmol/L (IQR 2.28-2.5). The average intraoperative PTH decrease was 75.6%. Of the 92 patients, 8 (8.7%) required multiple gland removal due to adenoma location differing to that indicated by preoperative imaging (3 were retrosternal). The biochemical cure rate within this cohort was 98%. 2 patients had no intraoperative PTH drop and persisting hypercalcaemia. They underwent further imaging and curative surgery. Conclusion: Intra-operative PTH monitoring is a useful adjunct to minimally invasive parathyroidectomy. 0721: PATIENT OUTCOME FOLLOWING LAPAROSCOPIC BILATERAL ADRENALECTOMY Carol Watson, Craig Parnaby, Patrick ODwyer. Gartnavel General Hospital,

The additional value of intraoperative parathyroid hormone assessment is marginal in patients with nonfamilial primary hyperparathyroidism: a prospective cohort study

BackgroundThe success of minimally invasive parathyroidectomy is attributed to evolving preoperative imaging techniques and intraoperative parathyroid hormone (IOPTH) measurement. The additional value of IOPTH measurement in patients undergoing surgery for primary hyperparathyroidism (pHPT) was evaluated. MethodsBetween 1999 and 2010 there were 119 patients who underwent surgery for pHPT at our institutions. In all patients, preoperative imaging was performed and IOPTH samples were collected prospectively but the results were not disclosed during surgery. ResultsPostoperative calcium level normalized in 114 patients (96%). The 5 surgical failures represented the maximum yield of IOPTH sampling. Three of these patients would have been identified intraoperatively by an inadequate IOPTH decrease, whereas IOPTH decreased inaccurately in the other 2 patients. In addition, in 1 of these 3 patients no abnormal gland was found during minimally invasive parathyroidectomy and subsequent conventional neck exploration. Therefore, only 2 reoperations would have been prevented (1.7%). ConclusionsIOPTH would have changed the outcome in 2 patients, increasing the biochemical cure rate from 96% to 98%. We believe that although it can be helpful in certain cases, it may not be necessary routinely in patients treated for pHPT.

Importance of intraoperative parathyroid hormone measurement in the diagnosis of parathyroid lipoadenoma

Parathyroid lipoadenoma is an uncommon tumor that may be difficult to diagnose on intraoperative frozen section. Intraoperative parathyroid hormone (PTH) measurement is useful in assessing the adequacy of parathyroidectomy. This case demonstrates the value of intraoperative PTH measurement in recognizing a parathyroid lipoadenoma. A case of a 62-year-old woman with primary hyperparathyroidism in which intraoperative PTH measurement helped confirm the diagnosis of parathyroid lipoadenoma is presented. In patients with primary hyperparathyroidism, a significant decrease in intraoperative PTH confirms that an enlarged parathyroid with normal to low cellularity containing abundant fat is a lipoadenoma and that further exploration is not necessary.

Intraoperative Parathyroid Hormone Monitoring in Patients with Recognized Multiglandular Primary Hyperparathyroidism

Intraoperative parathyroid hormone (IOPTH) monitoring reliably predicts cure of primary hyperparathyroidism (PHPT) due to single-gland disease. However, its utility in PHPT caused by multiple-gland disease (MGD) is still debated, for both detection and prediction of adequate resection. Our hypothesis is that once MGD is encountered during an operation, more stringent criteria for determining adequate resection can improve cure rates. This was a retrospective cohort study of patients with PHPT who were found to have MGD during the course of focused parathyroidectomy. IOPTH levels after completed multiple parathyroid gland excision were compared between cured patients and those with persistent hyperparathyroidism. Of 1855 patients undergoing focused parathyroidectomy, 243 were found to have MGD. Of the 207 study patients with MGD, 193 were cured and 14 had persistent hyperparathyroidism. After final gland excision, the mean±SEM percentage decrease in IOPTH from the baseline was of significantly greater magnitude for the cured group (90.0±0.5%) than for the persistent group (74.0±3.8%) (p<0.01). The mean±SEM IOPTH after completed multigland excision was higher in the persistent group (44.0±8.4 pg/ml) than in the cured group (34.0±3.5 pg/ml) (p=0.19), although both were within the normal range (12-65 pg/ml). When the groups were analyzed for an incremental fall of IOPTH from the baseline, the criteria of ≥75% drop and into the normal range improved the positive predictive value from 93.2 to 96.6% when compared to the standard criterion of a 50% decrease from the baseline. When PHPT due to MGD is recognized and focused parathyroidectomy is extended, a final postexcision PTH level that is ≥75% decreased from the baseline PTH level and in the normal range should be used to predict adequate gland resection.

Usefulness of intraoperative parathyroid hormone measurements in patients with renal hyperparathyroidism

In renal hyperparathyroidism, it remains unclear whether intraoperative parathyroid hormone (PTH) measurements can predict postoperative outcome and guide the extent of surgical exploration. In 42 parathyroidectomies for renal hyperparathyroidism, we analyzed the predictive value of the Miami Criterion of 50% intraoperative PTH decrease. We used receiver operating characteristic (ROC) curves to find the criterion with the best diagnostic performance. We also investigated whether the whole PTH assay improved accuracy. Twenty-six operations (62%) resulted in normal postoperative PTH. With the Miami Criterion, cure was predicted with a sensitivity of 95% and specificity of only 8%. Specificity could be improved to 50% using a 70% PTH decrease as cut-off level. The whole PTH assay did not improve accuracy. Prediction of cure after parathyroidectomy for renal hyperparathyroidism might be improved with a criterion of 70% PTH decrease 10 minutes after excision of all parathyroid glands. Prospective analysis needs to validate this new criterion.

Long-term outcome of patients with intraoperative parathyroid level remaining above the normal range during parathyroidectomy

Criterion requiring intraoperative parathyroid hormone (IOPTH) drops >50% from the highest, preincision or preexcision level, 10 minutes after the abnormal gland's excision predicts operative success with 98% accuracy. The purpose of this study is to correlate IOPTH dynamics with recurrent hyperparathyroidism (RecHPT) and eucalcemia with high PTH (HPTH). We followed 383 consecutive patients with parathyroidectomy guided by IOPTH monitoring using the above criterion for >6 months. Calcium and PTH levels were measured for 50 months (range, 6-173). Patients were divided in 2 groups: group 1 comprised 302 participants with IOPTH levels that decrease to the normal range (NR), and group 2, with 81 participants who had >50% IOPTH decrease but remained above the normal range. The incidence of RecHPT and eucalcemia with HPTH was evaluated. RecHPT was found in 2% (8/383) of patients and eucalcemia with HPTH was present in 19% (74/383). In group 1, 17% (52/302) had eucalcemia with HPTH, whereas in group 2, this incidence was 27% (22/81; P = .04). However, only 2% of those (6/302) in group 1 and 2.5% (2/81) in group 2 developed RecHPT (P = .76). Conversely, 70.5% of those (57/81) in group 2 were eucalcemic with normal PTH. Although postoperative eucalcemia with HPTH was significantly higher among patients with IOPTH above the normal range than in patients in group 1, the incidence of RecHPT was not increased. The majority of patients in whom IOPTH did not drop to the normal range continue to be biochemically normal after the operation.

Interpretation of intra-operative PTH changes in patients with multi-glandular primary hyperparathyroidism (pHPT)

The correct interpretation of intraoperative parathyroid hormone (IOPTH) levels in patients with primary hyperparathyroid patients (pHPT) with multiglandular disease (MGD) can impact the success rate of initial parathyroid exploration, but it remains an understudied topic. In all, 592 of 823 patients were explored by a single surgeon with biochemical evidence of pHPT (1997-2007) and underwent parathyroidectomy using IOPTH. We investigated the incidence of MGD in patients with an appreciable (>50%) decrease in IOPTH levels and in patients whose levels failed to normalize after single gland excision. The mean age of patients was 56.7 years, and 74% of patients were women. Thirty-one patients had PTH levels that decreased by greater than 50% from baseline 10-15 min after single gland excision, but the levels failed to normalize. Of these, 9 patients (29%) had MGD (8 double adenomas, 1 hyperplasia). The incidence of MGD in the remainder of IOPTH patients was 13.9% (78 of 561 patients). Within the subgroup of 31 patients, those with single adenomas did not differ from patients with MGD in baseline IOPTH levels and weights of first adenoma excised, although they demonstrated greater serum creatinine concentrations and a decrease in mean IOPTH. Commonly accepted decreases in IOPTH levels (>50%) for patients who undergo minimally invasive parathyroidectomy may lead to an appreciable number of missed parathyroid adenomas or hyperplastic disease.