Consequences of targeted parathyroidectomy guided by localization studies without intraoperative parathyroid hormone monitoring

BACKGROUND: After excision of an abnormal gland, the dynamics of intraoperative parathyroid hormone (PTH) levels signal whether or not more hypersecreting tissue is present. This quantitative assurance of operative success has led to targeted exploration of the hyperfunctioning gland(s). Some have questioned the need for intraoperative PTH monitoring (IPM) in the presence of positive nuclear scanning. The purpose of this study was to examine the accuracy of nuclear scans in correctly localizing and guiding the complete excision of all abnormal gland(s) in patients with sporadic primary hyperparathyroidism (SPHPT) and to demonstrate how IPM changed the operative management in these patients. STUDY DESIGN: Five hundred nineteen consecutive patients with sporadic primary hyperparathyroidism had technetium 99-m-sestamibi scans (MIBI) as localization studies obtained before undergoing parathyroidectomy guided exclusively by IPM. All patients were either followed for more than 6 months, or their procedures were identified as operative failures. MIBI reports were correlated with operative findings, hormone dynamics, and postoperative outcomes. RESULTS: Operative success was achieved in 506 of 519 patients (97%). MIBI correctly localized all involved glands in 411 patients (80%). Among the 105 patients (20%) with incorrect or negative scans, IPM changed the operative management in 86 of 105 (82%) by pointing out incomplete resection in patients with a single MIBI incorrect focus (21 of 28) or unrecognized multiglandular disease by scan (13 of 15); avoiding unnecessary exploration in patients with additional incorrect foci (20 of 21); and guiding the surgeon to successful excision or unilateral neck exploration in patients with negative MIBI (32 of 41). CONCLUSIONS: MIBI as a single adjunct missed 87% of patients with multiglandular disease. Including patients with negative (8%) and incorrect (12%) MIBI, IPM changed the operative management in 17% of patients and led to operative success in 97%. We suggest that IPM should be used to guide parathyroid excision in every patient with sporadic primary hyperparathyroidism.     

Late parathyroid function after successful parathyroidectomy guided by intraoperative hormone assay (QPTH) compared with the standard bilateral neck exploration

BACKGROUND: Controversy continues between bilateral neck exploration and limited parathyroidectomy. One approach depends on gland size and histopathologic factors; the other approach limits excision to only hypersecreting glands. Both have excellent early operative success, but late recurrence rates with limited exploration are unknown. METHODS: Three hundred twenty consecutive patients with primary hyperparathyroidism were followed 6 to 313 months after successful parathyroidectomy. One hundred seventy-six patients had bilateral neck exploration with excision of enlarged glands (group I); 144 patients had glands excised based on hyper-secretion (group II). Calcium and intact parathyroid hormone (iPTH) levels were measured yearly. Parathyroid gland hypersecretion was determined by elevated iPTH levels. RESULTS: In group I, 1 gland was excised in 160 patients (91%); 19 of 176 patients (11%) had elevated iPTH levels. In group II, 139 patients (97%) had 1 gland excised; 19 of 144 patients (13%) had high iPTH levels. The number of patients with more than 1 gland excised in group I (9%) is 3 times higher than in group II (3%) (P <.05). There was no significant difference in the incidence of recurrent hyperfunctioning glands between the 2 different operative approaches (chi-squared test). CONCLUSIONS: Late parathyroid gland function was comparable with both approaches. Multiple gland excision based on size alone may lead to excision of normal functioning glands.     

99mTc-sestamibi Scintigraphy and Cell Cycle in Parathyroid Glands of Secondary Hyperparathyroidism

Double-phase parathyroid MIBI (^99mTc-sestamibi) was performed in 27 patients with secondary hyperparathyroidism (SPT). Focal areas of increased uptake were scored for intensity on a three-point scale. All patients underwent subtotal parathyroidectomy (SPTx), and a total of 78 glands were removed at operation. Blood was obtained from the jugular vein before and after SPTx to measure the parathyroid hormone (PTH) levels. The volume and weight of the glands were calculated. The tissue was divided, with one aliquot being used for cell cycle analysis. The nuclei were acquired by flow cytometry and analyzed using CELLEIT software. Cell viability was assessed by flow cytometry and analyzed with LYSIS II software. Positive MIBI uptake was observed in 88.8% of patients. Focal MIBI uptake of one, two, or three glands was observed in 6, 11, and 8 patients, respectively. All patients experienced an 86% decrease in PTH blood level after SPTx compared to that before excision. A correlation was found between the volume of glands and the blood levels of intact PTH (iPTH) (r= 0.5, p < 0.05). A positive correlation was observed between MIBI uptake and the iPTH levels before SPTx (p < 0.01) and between the uptake of MIBI in the parathyroid glands and the cell cycle phases; low-grade uptake correlated with the G₀ phase and higher uptake with G₂+S phase (r= 7, p < 0.01). No correlation was observed between MIBI uptake and the weight of the glands. MIBI scintigraphy accurately reflects the functional status of the hyperplastic parathyroid glands: Higher uptake grades correlated with the active growth phase. MIBI uptake does not reveal parathyroid enlargement; rather, it identifies the presence of hyperfunctioning autonomous glands. SPTx and total parathyroidectomy with autografting (TPTx+A) are the most widely accepted surgical approaches for patients with SPT. Reoperation for recurrence is necessary in 6% to 15% of cases. MIBI is now considered to be the radionuclide of reference for parathyroid gland scanning, although it is widely accepted that it produces poor results when trying to detect hyperplastic glands.     

Clinicopathologic and radiopharmacokinetic factors affecting gamma probe-guided parathyroidectomy

HYPOTHESIS: The kinetics of technetium Tc 99m sestamibi (MIBI) in primary hyperparathyroidism are variable and affected by the cellular size of the abnormal glands, the parathyroid hormone levels, and the functional expression of P-glycoprotein (Pgp). The success of gamma probe-guided parathyroidectomy is closely related to the parathyroid-to-thyroid activity ratio at the time of surgery. Preoperative determination of maximum uptake ratio may improve the surgical outcome. DESIGN: Thirty-one patients with primary hyperparathyroidism attributed to a solitary parathyroid adenoma (27 patients) or multiglandular hyperplasia (4 patients) underwent dynamic MIBI imaging preoperatively. Maximum MIBI activity and activity elimination half-life in the abnormal parathyroid glands and thyroid glands were measured, and the maximum uptake ratio was calculated. After a second MIBI injection on the day of surgery, all patients underwent gamma probe-guided parathyroidectomy and cervical exploration. Timing of surgery after MIBI injection was individualized according to the optimal time to surgery (time to maximum uptake ratio), which was determined by preoperative scintigraphy. During surgery, the gamma probe was used to measure ex vivo counts of excised lesions and adjacent postexcision normal tissue (background). Image characteristics, MIBI kinetics, and gamma probe findings were correlated with gland volume, oxyphil cell content, Pgp expression, and serum parathyroid hormone levels. RESULTS: Probe localization of abnormal glands at maximum uptake ratio was successful in all patients. The volume of the parathyroid lesion ranged from 0.03 to 9.8 mL (median, 0.7 mL). Parathyroid maximum MIBI activity correlated with the volume of the gland (r = 0.54, P = .002) and serum parathyroid hormone level (r = 0.58, P = .001). No correlation between maximum MIBI activity and oxyphil cell content or Pgp expression could be demonstrated. Elimination half-life of MIBI from parathyroid inversely correlated with Pgp (r = -0.36, P = .05). The ex vivo lesion-background count ratio positively correlated with volume of the gland (r = 0.66, P = .001) and parathyroid hormone level (r = 0.48, P = .006). Ex vivo lesion counts and Pgp expression were negatively correlated (r = -0.37, P = .04). CONCLUSIONS: A strong relationship between volume of the parathyroid gland, serum parathyroid hormone levels, and MIBI uptake exists in primary hyperparathyroidism. Gamma probe-guided localization of abnormal gland(s) can be more successful if surgery is undertaken at maximum uptake ratio. High Pgp expression increases MIBI parathyroid clearance rate, decreases gamma probe counts, and may significantly alter the optimal time to surgery.     

Minimally invasive endoscopic-assisted parathyroidectomy for primary hyperparathyroidism

Background: Minimally invasive surgery for primary hyperparathyroidism (pHPT) depends on both an accurate preoperative localization and the availability of intraoperative parathyroid hormone monitoring. Methods: Patients with sporadic pHPT and one unequivocally enlarged parathyroid gland on preoperative imaging underwent endoscopic-assisted parathyroidectomy. Intraoperative rapid parathyroid hormone (quick PTH) monitoring was performed, and surgical success was confirmed when there was a >50% decrease in quick PTH level 10 min after excision as compared with the baseline level at induction. The surgical outcome and the use of preoperative localization, together with the role played by quick PTH assay in enhancing the operative success, were evaluated. Results: From 1999 to 2002, 66 of 107 patients (62%) were selected for this approach. The accuracy of ^99mTc-Sestamibi scintigraphy and ultrasonography was 97% and 70%, respectively. Conversion was required in four cases due to technical problems, and four additional patients failed to show a significant decline in quick PTH levels postexcision. Two patients underwent cervical exploration without the finding of any additional pathology, and another two patients had a delayed drop in quick PTH that was confirmed 30 min postexcision. All patients had a solitary adenoma and were cured of hypercalcemia during a median follow-up of 9 months. Conclusions: Minimally invasive endoscopic-assisted parathyroidectomy can be performed expeditiously in a select group of patients based on ^99mTc-Sestamibi scintigraphy. The use of quick PTH assay can ensure surgical success, but careful interpretation of the results is mandatory.     

The Rationale for performing MR Imaging before Surgery for Primary Hyperparathyroidism

Objective : The purpose of this study was to evaluate prospectively Magnetic Resonance Imaging (MRI) for the preoperative localization of hyperfunctioning parathyroid glands.

Design : Prospective study of 58 consecutive patients with biochemically confirmed primary hyperparathyroidism who

underwent preoperative MRI.

Setting : The setting is a referral centre.

Patients : Fifty-six of the 58 consecutive patients (41 women, 17men) were studied by both preoperative MRI and ^99mTC MIBI scintigraphy, and two by MRI alone. The same surgeon, using the information from both MRI and ^99mTC MIBI, performed surgery in 58 patients, including 19 with a history of neck surgery. Initial interpretation of each MR study was done independently by one radiologist and the surgeon and then results were compared. At surgery, the operative duration, the precise anatomical location, weight, and dimensions as well as complete histopathological evaluations of all excised glands were recorded.

Main outcome measure : In addition to the prospective assessment of MRI, this study compared performance of MRI with double-phase ^99mTC MIBI scintigraphy for preoperative localization of hyperfunctioning parathyroid glands. Results : All patients became normocalcaemic after surgery. MRI and ^99mTC MIBI imaging revealed 53 of 58 (91%) and 47 of 56 (84%) of abnormal glands, respectively. Sensitivities of MRI and ^99mTC MIBI were respectively 94.3 and 88.0. Positive predictive values were 96.15 and 93.60. When MRI and ^99mTC MIBI were interpreted together, the sensitivity and positive predictive values both raised to 98.10. Median operative duration was 30 minutes (ranges 20–300 minutes, mean 65).

Conclusion : MRI has better sensitivity and positive predictive value than ^99mTC MIBI scintigraphy for the detection of hyperfunctioning parathyroid glands. The combination of the two studies provides an additional increase in sensitivity and positive predictive value leading to a more precise anatomical localization of the abnormal parathyroid glands reducing both the extent of the surgical dissection and the operative duration.     

Usefulness of 99mTc-methoxy-isobutyl-isonitrile scintigraphy for preoperative localization of adenoma in primary hyperparathyroidism]

We evaluated the usefulness of 99mTc-methoxy-isobutyl-isonitrile (MIBI) dual phase scintigraphy for detecting hyperfunctioning parathyroid adenoma. We retrospectively reviewed 18 hyperparathyroid patients who received MIBI prior to neck exploration and compared the radiological findings of MIBI with ultrasonography (US) and magnetic resonance imaging (MRI). Fifteen patients were studied with MRI, and 17 patients were examined with US. All patients were found to have a solitary parathyroid adenoma histopathologically. MIBI correctly revealed the location of 17 adenomas among 18 confirmed tumors. In our series, there was one false-positive case that was found to have thyroid adenoma. The diagnostic sensitivity of MIBI MRI and US was 94.4%, 80% and 52.5%, respectively. The positive predictive value (PPV) was 94.4% for MIBI, 81.8% for MRI and 92.3% for US. We conclude that MIBI is useful and accurate for the preoperative localization of adenoma in primary hyperparathyroidism.     

Minimally invasive video-assisted parathyroidectomy

BACKGROUND: The standard surgical procedure for parathyroidectomy consists of bilateral cervical exploration and the visualization of all four parathyroid glands. However, improved preoperative localization techniques and the availability of intraoperative intact parathyroid hormone (iPTH) monitoring now allow single adenomas to be treated with minimally invasive techniques. METHODS: Patients with primary hyperthyroidism (pHPT), who were found to have one unequivocally enlarged parathyroid gland on preoperative ultrasound and 99mTc-SestaMIBI scintigraphy underwent minimally invasive video-assisted parathyroidectomy by an anterior approach. Intraoperatively, rapid electrochemiluminescense immunoassay was used to measure iPTH levels shortly before and 5, 10, and 15 mins after excision of the adenoma. The operation was considered successful when a >50% decrease in preexcision iPTH levels was observed after 5 min. RESULTS: Between November 1999 and May 2000, 10 of 22 patients with pHPT were deemed eligible for the minimally invasive approach. In all cases, the adenoma was removed successfully. However, in two cases, intraoperative iPTH monitoring did not show a sufficient decrease in iPTH values. Subsequent cervical exploration revealed a double adenoma in one case and hyperplasia in the other. CONCLUSIONS: Even when high-resolution ultrasound and 99mTc-SestaMIBI scintigraphy are used, the presence of multiple glandular desease cannot be ruled out entirely. When the minimally invasive approach is contemplated, intraoperative iPTH monitoring is indispensible to ensure operative success. However, in selected cases, minimally invasive parathyroidectomy represents an excellent alternative to the conventional technique.     

Minimally invasive video-assisted parathyroidectomy and intraoperative parathyroid hormone monitoring. The first 36 cases and some pitfalls

Background: The success of parathyroid surgery depends on the identification and removal of all hyperactive parathyroid tissue. At this writing, bilateral cervical exploration and identification of all parathyroid glands represent the operative standard for primary hyperparathyroidism (pHPT). However, improved preoperative localization techniques and the availability of intraoperative parathyroid hormone monitoring prepare the way for minimally invasive procedures. Methods: Patients with pHPT and one unequivocally enlarged parathyroid gland on preoperative ultrasound and 99mTc-SestaMIBI scintigraphy underwent minimally invasive video-assisted parathyroidectomy by an anterior approach. Intraoperatively, a rapid chemiluminescense immunoassay was used to measure intact parathyroid hormone (iPTH) levels shortly before and then 5, 10, and 15 min after excision of the adenoma. The operation was considered successful when more than a 50% decrease in preexcision iPTH levels was observed after 5 min. Results: Between October 1999 and November 2001, 36 of 82 patients with pHPT were eligible for a minimally invasive approach. A conversion to open surgery became necessary in five patients because of technical problems. In three cases, intraoperative iPTH monitoring showed no sufficient decrease in iPTH values. In these cases, subsequent cervical exploration showed one double adenoma and two hyperplasias, respectively. In two patients we had difficulty interpreting intraoperative iPTH values, resulting in persistent pHPT. Conclusions: Despite the use of high-resolution ultrasound and 99mTc-SestaMIBI scintigraphy, the presence of multiple glandular disease cannot be ruled out completely. Intraoperative iPTH monitoring to ensure operative success is indispensible for a minimally invasive approach. Despite our problems with iPTH monitoring in two patients, we believe that in selected cases, minimally invasive parathyroidectomy represents an attractive alternative to conventional surgery.     

Novel parathyroid hormone (1-84) assay as basis for parathyroid hormone monitoring in renal hyperparathyroidism

HYPOTHESIS: Cross-reactivity of parathyroid hormone (PTH) fragments with immunometric "intact" PTH assays limited the use of intraoperative PTH monitoring in renal hyperparathyroidism. A new assay generation measuring whole PTH (1-84) should be able to predict complete or incomplete resection of hyperfunctioning parathyroid tissue. DESIGN: Consecutive series for evaluation of intraoperative PTH monitoring using a second-generation assay. SETTING: University hospital section of endocrine surgery. PATIENTS: Twenty-two patients received hemodialysis; 9 patients showed good and 4 patients reduced graft function after kidney transplantation. INTERVENTIONS: Total parathyroidectomy, central neck dissection, bilateral thymectomy, and immediate autotransplantation was the standardized approach in 35 consecutive patients. Blood samples were drawn before incision and at 5-minute intervals after excision of the last gland. Stored samples were analyzed using a "second-generation" assay (Bio-Intact PTH [1-84]; Nichols Institute Diagnostics, San Clemente, Calif). Parathyroidectomy was classified as total, subtotal, or insufficient according to first-generation intact PTH values in the first postoperative week. MAIN OUTCOME MEASURES: Intraoperative ability to predict total, subtotal, or incomplete parathyroidectomy. RESULTS: Independent of renal function, Bio-Intact PTH dropped into the normal range in all patients with total and subtotal resections after a maximum of 20 minutes. It indicated insufficient parathyroidectomy in 4 (80%) of 5 patients. One failure was caused by devascularization of remaining parathyroid tissue. An intraoperative differentiation between total and subtotal resection was not possible. CONCLUSIONS: Intraoperative monitoring with quick, second-generation assays for PTH (1-84) seems to be a valuable new tool in surgery for renal hyperparathyroidism because a more accurate differentiation between sufficient and insufficient parathyroidectomy may be achieved. An intraoperative decision about the need for immediate or delayed autotransplantation seems impossible because a differentiation between total or subtotal parathyroidectomy cannot be made. Because of possible devascularization of parathyroid tissue, Bio-Intact PTH monitoring can only be interpreted in the context of the operative findings.     

Intraoperative sestamibi scanning in reoperative parathyroidectomy

BACKGROUND: Reoperative neck exploration for hyperparathyroidism is often difficult even for experienced surgeons. Recent advances in preoperative and intraoperative localization techniques have improved successful resection rates. This prospective study evaluates the accuracy and clinical utility of intraoperative technetium 99m sestamibi scanning for localizing hyperfunctioning parathyroid tissue in reoperative neck explorations. PATIENTS AND METHODS: Eleven patients underwent reoperative neck exploration for hyperparathyroidism. Two patients had 3 prior neck explorations, 1 had 2 prior neck explorations, and 8 patients had 1 prior neck operation. Preoperative studies included sestamibi scintigraphy and ultrasound in all patients, magnetic resonance imaging in 4, computed tomography scan in 3, parathyroid arteriogram in 1, and selective venous sampling in 1. All patients underwent intraoperative technetium 99m sestamibi scanning and parathyroid hormone assay. RESULTS: Preoperative technetium 99m sestamibi scanning and ultrasound each successfully localized 7 of 11 hyperfunctioning glands (64%). Intraoperative technetium 99m sestamibi scanning correctly localized 10 of 11 hyperfunctioning glands (91%). Intraoperative parathyroid hormone assay confirmed successful excision of hyperfunctioning tissue in all 11 patients. Postoperatively, all 11 patients had low-normal or normal calcium levels. CONCLUSIONS: Intraoperative technetium 99m sestamibi correctly localized 91% of hyperfunctioning glands compared with 64% localization for preoperative technetium 99m sestamibi and preoperative ultrasound. Intraoperative technetium 99m sestamibi scanning and parathyroid hormone monitoring are useful in reoperative neck explorations for hyperparathyroidism.     

Technetium-99m methoxy isobutyl isonitrile (MIBI) imaging of the parathyroid glands in patients with renal failure

Background. Technetium-99m methoxy isobutyl isonitrile (Tc-99m MIBI) scintigraphy has been reported to be at least as reliable as thallium-technetium subtraction imaging in the preoperative localization of hyperplastic parathyroid glands in patients with renal failure. Reports have suggested that 50% of glands can be identified correctly by this method. The aim of this study was to improve on previous results and demonstrate that Tc-99m MIBI imaging has an important place in the preoperative work-up of these patients. Methods. Eighteen patients on renal replacement therapy were studied. All had tertiary hyperparathyroidism and had Tc-99m MIBI imaging prior to parathyroidectomy. A refined reporting method was employed. The imaging results were compared to the subsequent surgical and histological findings. Results. In the 12 patients in whom serum parathyroid hormone levels fell postoperatively to within or below the normal range, 38 of 46 glands (82.6%) were correctly identified and located in the correct quadrant of the thyroid gland. There were two false positive results where the imaging predicted glands not subsequently found by the surgeon. In the patients who had post-operative hyperparathyroidism, repeat Tc-99m MIBI imaging was able to locate accurately the site of the residual parathyroid tissue. Conclusion. Tc-99m MIBI imaging is able to identify more than 80% of hyperplastic parathyroid glands in renal failure patients if this reporting process is used, and locate them in the correct quadrant of the thyroid gland. Tc-99m MIBI imaging is of particular value when re-exploration of the neck is required for post-parathyroidectomy hyperparathyroidism. These results represent a significant improvement on the sensitivity of this imaging technique when compared to previous published data.     

原发性甲状旁腺机能亢进患者术中监测甲状旁腺激素的临床意义

目的：探讨原发性甲状旁腺机能亢进症（PHPT）患者术中动态监测甲状旁腺激素（IOPTH）的临床价值。 方法：回顾性分析1998年1月—2012年1月行手术治疗的36例PHPT患者的临床资料,其中2005年以后术中行IOPTH监测患者22例（IOPTH组）,2005年以前术中未行IOPTH监测的患者14例（常规组）,比较两组的术中情况与治疗效果。 结果：与常规组比较,IOPTH组手术时间明显缩短[（72.95±24.34）min vs.（81.86±29.46）min,P=0.000],术后短期（1个月内）甲状旁腺功能恢复患者比例增加（90.9% vs. 57.1%,P=0.018）,永久性甲状旁腺功能减退发生率明显减少（4.5% vs. 28.6%,P=0.042）。IOPTH监测对于判断高功能病灶完全切除与否的敏感度为100%,准确率为95.5%。 结论：PHPT手术中,在术前定位基础上联合IOPTH,有助于判断功能亢进腺体是否全部切除,避免遗漏多发病变腺体及不必要的双侧探查,缩短手术时间,疗效确切。     

Operative monitoring of parathyroid gland hyperfunction.

With a 20-year experience of more than 700 parathyroidectomies, our persistent hypercalcemic postoperative failure rate of 7% has remained constant. Reasons for failure have been misdiagnosis or inability of the surgeon to detect and excise all hypersecreting glands. We have modified a commercially available immunoradiometric assay for intact parathyroid hormone (PTH) resulting in a 15-minute turnaround time. Since intact PTH has a half-life measured in minutes, whole blood samples taken 10 minutes after gland excisions were monitored intraoperatively to confirm significant changes in circulating hormone. Quantitative evidence that all hyperfunctioning parathyroid tissue had been ablated during operation was obtained in 19 of 21 patients. Less than four glands each were identified in 53% of these patients. The PTH "quick" test correctly pointed to an inadequate excision requiring further parathyroid ablation in two patients, made bilateral neck exploration unnecessary in two patients who had previously undergone parathyroidectomy, and predicted persistent hypercalcemia in two patients with complications.     

Sestamibi scanning and minimally invasive radioguided parathyroidectomy without intraoperative parathyroid hormone measurement

OBJECTIVE: To evaluate the results of a large series of patients undergoing minimally invasive radioguided parathyroidectomy (MIRP) in which routine use of the intraoperative parathyroid hormone assay was not used, and to investigate characteristics between patients who had positive preoperative parathyroid scans versus those with negative scans. SUMMARY BACKGROUND DATA: The technique of parathyroidectomy has traditionally involved bilateral exploration of the neck under general endotracheal anesthesia. Parathyroid imaging using technetium-99m sestamibi (MIBI) has evolved and can localize the adenomas in 80% to 90% of patients. The MIRP technique combines parathyroid scintigraphy with a hand-held gamma detector used intraoperatively to guide the surgeon to the adenoma in patients with positive MIBI scans. Central to this technique or other unilateral approaches is a positive MIBI scan. METHODS: One hundred seventy-three patients with primary hyperparathyroidism operated on by a single surgeon between January 1998 and July 2002 were included. One hundred twelve patients underwent the MIRP procedure and by definition had a positive preoperative parathyroid scan. The technique involved injecting 20 mCi MIBI 1 hour before the surgical procedure in patients who preoperatively had positive MIBI imaging. Patients had the choice of general or MAC anesthesia. Using an incision of less than 4 cm, the dissection to the adenoma was guided by the Navigator 11-mm probe. These 112 patients and 4 additional patients who for various reasons did not have the MIRP procedure yet had positive MIBI scans were compared to 57 patients who had clearly negative MIBI parathyroid imaging. RESULTS: Follow-up data were available for 108 of 112 patients who underwent MIRP. No patients had persistent hypercalcemia. The long-term success rate for the MIRP group was 98%. Fifty-two percent of the MIRP procedures were performed using MAC anesthesia. Overall, gland weight and serum PTH were related to the probability of a positive MIBI scan. Multiple logistic regression revealed that females were more likely to exhibit positive scans than were males for any fixed serum PTH level. For females, there was a significant relationship between increasing serum parathyroid hormone and a positive MIBI scan. Conversely, in males, the relationship between scan positivity and serum parathyroid hormone was weaker. CONCLUSIONS: The MIRP technique without routine intraoperative serum parathyroid hormone measurement resulted in an excellent cure rate for primary hyperparathyroidism. As the MIRP technique as well as other techniques for unilateral cervical exploration are predicated on a positive parathyroid scan, the possible effect of gender on the sensitivity of MIBI scintigraphy for the detection of parathyroid adenomas warrants further investigation.     

Secondary and tertiary hyperparathyroidism: role of preoperative localization

BACKGROUND: The usefulness of both technetium Tc-99m sestamibi (MIBI) scintigraphy and ultrasonography (USG) scan for the detection of enlarged parathyroid glands secondary to renal hyperparathyroidism is rarely addressed. METHODS: A retrospective study from July 1999 to June 2005 was carried out on patients with secondary and tertiary hyperparathyroidism to determine the role of preoperative localization. RESULTS: In the 5 years, 73 patients with renal hyperparathyroidism underwent initial bilateral neck exploration with total parathyroidectomy. Four patients underwent neck exploration with parathyroidectomy for persistent hyperparathyroidism. Two patients underwent neck exploration with parathyroidectomy for recurrent hyperparathyroidism. For patients with initial secondary/tertiary hyperparathyroidism, MIBI scintigraphy correctly showed 101 of 276 (36.6%) surgically confirmed enlarged parathyroids, whereas USG scan showed 99 of 276 (35.9%) surgically confirmed enlarged parathyroids. For persistent or recurrent secondary/tertiary hyperparathyroidism, MIBI scintigraphy and USG scan had sensitivity of 100 and 50%, respectively. CONCLUSIONS: In conclusion, preoperative localization studies have a limited value when used before first neck exploration in secondary/tertiary hyperparathyroidism because of the poor results in identifying all parathyroid glands. In persistent/recurrent hyperparathyroidism, it may play a useful role in localization of the missed or ectopic parathyroid gland.     

Quick PTH assay cannot predict incomplete parathyroidectomy in patients with renal hyperparathyroidism

BACKGROUND: Contradictory reports on the value of intraoperative quick parathyroid hormone (PTH) monitoring in renal hyperparathyroidism have been published. METHODS: Thirty-five consecutive patients underwent total parathyroidectomy, central neck dissection, bilateral thymectomy, and immediate autotransplantation. PTH levels were measured by PTH assay at induction of anesthesia (baseline level) and in 5-minute intervals after excision of the last parathyroid gland. Parathyroidectomy was considered "total" in patients with PTH levels <10 pg/mL (subgroup 1), "subtotal" between 10 and 65 pg/mL (subgroup 2) and "insufficient" at >65 pg/mL (subgroup 3) within the first postoperative week. RESULTS: Fifteen minutes after excision of the last gland, PTH levels dropped to 19.4 +/- 15.7% (subgroup 1), 14.9 +/- 5.9% (subgroup 2), and 18 +/- 6.7% (subgroup 3) from baseline among 22 patients on hemodialysis, to 22.1 +/- 18.7% and 17.5% in 9 patients (subgroups 1 and 2) after successful kidney transplantation, and to 10.7% and 17.5% (subgroup 1) and 12.8% and 31.4% (subgroup 2) in 4 patients with reduced renal function after kidney transplantation. CONCLUSIONS: Currently available QPTH assays are not useful to predict insufficient resection of hyperfunctioning parathyroid tissue.     

Does Intraoperative Quick Parathyroid Hormone Assay Improve the Results of Parathyroidectomy?

Preoperative sestamibi (MIBI) and ultrasonography (US) are used to localize parathyroid tumors in patients with primary hyperparathyroidism (pHPT). The intraoperative quick PTH assay (qPTH) has been recommended to determine whether all hyperfunctioning parathyroid tissue has been removed. We questioned whether qPTH improves the results of parathyroidectomy in patients with pHPT. We analyzed 115 unselected patients with pHPT without a family history or multiple endocrine neoplasia but who had undergone parathyroidectomy. All 115 patients had successful operations without complications. Of these patients, 88 (77%) had solitary adenomas, 13 had double adenomas, 1 had triple adenomas, 12 had hyperplasia, and 1 had carcinoma. Overall, MIBI was correct in 72% (76/106), US in 49% (49/99), and qPTH in 80% (92/115). For preoperative studies showing a single tumor, MIBI was correct in 83% (73/88), US was correct in 71% (45/63), and combined MIBI and US were correct in 95% (37/39). Adding qPTH in this subgroup did not improve the successful focused approach: 70% for MIBI, 65% for US, and 87% for combined MIBI and US. However, adding qPTH improved the overall success of parathyroidectomy (MIBI 92%, US 86%, combined MIBI and US 97%), but at the cost of unnecessary further exploration (MIBI 13%, US 6%, combined MIBI and US 8%). We conclude that when the same solitary tumor is identified by both MIBI and US, a focused exploration can be done with a 95% success rate. Adding qPTH to MIBI or US can improve the success rate but at a significant cost. General exploration of all parathyroid glands, however, has the highest success rate (100%).     

Preoperative technetium Tc 99m sestamibi SPECT imaging in the management of primary hyperparathyroidism in patients with concomitant multinodular goiter

HYPOTHESIS: Preoperative parathyroid and thyroid imaging using technetium Tc 99m sestamibi scintigraphy-single-photon emission computed tomography (Tc 99m MIBI SPECT) and technetium Tc 99m sodium pertechnetate, respectively, in patients with parathyroid adenomas and concomitant multinodular goiters enables the selection of those suitable for minimally invasive radio-guided surgery. DESIGN: One hundred thirty patients with primary hyperparathyroidism were treated surgically during a 30-month period. Forty-one of these 130 patients had an associated multinodular goiter. All patients underwent planar and SPECT parathyroid scintigraphy using Tc 99m MIBI, and thyroid scintigraphy with technetium Tc 99m pertechnetate 2 to 5 days before surgery. On the morning of surgery each patient was reinjected with Tc 99m MIBI for intraoperative localization and validation. Minimally invasive radio-guided parathyroidectomy was performed using a handheld gamma-detection device with a thyroid probe. Removed glands were submitted for histopathologic examination for comparison with the scintigraphic results. Quantitative analysis of parathyroid activity was performed. RESULTS: Minimally invasive, radioguided parathyroidectomy was successfully performed in 21 (51%) of 41 patients who had a concomitant multinodular goiter. The remaining 20 patients underwent standard neck exploratory surgery because of associated thyroid disease; 5 of them had malignant thyroid disease. Among the 41 patients planar scintigraphy correctly identified 28 adenomas (68%). Single-photon emission computed tomographic imaging identified an additional 11 adenomas for a sensitivity of 95% and a specificity of 100%. Moreover, SPECT imaging correctly identified malignant thyroid nodules in 4 of 5 patients. Technetium Tc 99m MIBI retention was noted in only 25 adenomas (61%) while the remaining adenomas demonstrated a rapid washout. The average uptake ratio of parathyroid counts to maximum thyroid activity was significantly correlated with parathyroid hormone levels before surgery (P = .04). CONCLUSIONS: Our data encourage the use of preoperative SPECT imaging of parathyroid adenomas in patients who have multinodular goiters to select those suitable for minimally invasive radioguided surgery. This technique also offers important information regarding thyroid nodules that are suspicious for malignancy. The intraoperative gamma-probe technique enables the surgeon to focus his or her search, provides instant feedback regarding the progress of the operation, reduces surgical trauma and complications, and yields better cosmetic results. Patients with higher presurgical parathyroid hormone levels may especially benefit from radioguided surgery.     

Preoperative localization of supernumerary and ectopic parathyroid glands in patients with secondary hyperparathyroidism

The undetectable supernumerary and ectopic parathyroid glands have a high risk of persistent and recurrent hyperparathyroidism, especially in the patients with secondary hyperparathyroidism. Preoperative image diagnosis, CT scan, echogram and 201T1C1 scintigram were very useful for detecting supernumerary and ectopic parathyroid glands in our 132 patients who underwent parathyroidectomy for secondary hyperparathyroidism. Among these methods the scintigraphy showed the highest detection rate of the glands in the thymic tongue and in the upper mediastinum. CT scan showed the best detection rate of the glands located in the thyroid gland and those located between the thyroid gland and trachea. The echography was useful in detecting the glands in the thyroid gland, but could not offer easy visualization those located in the mediastinum. Even the ectopic parathyroid glands, weighing more than 500 mg were identifiable at about 90% when all the methods were applied routinely. In our experience, four patients had a supernumerary gland which was detected by the preoperative image diagnostic procedures at the initial surgery. One patient had a supernumerary gland in the mediastinum which was detected by image diagnosis after the initial operation and was removed at reoperation.