Intraoperative quick parathyroid hormone versus same-day parathyroid hormone testing for minimally invasive parathyroidectomy: a cost-effectiveness study

Intraoperative parathyroid hormone measurement pitfalls: parathyroid hormone spikes with carboxyl-terminal parathyroid hormone fragments in primary hyperparathyroidism-a case report

BACKGROUND

Intraoperative parathyroid hormone (IOPTH) monitoring is a critical surgical adjunct for determining the extent of surgery for primary hyperparathyroidism (PHPT), with reported false-positive and false-negative rates of up to 10%. Surgeons must understand the parathyroid hormone (PTH) dynamics and select the appropriate IOPTH protocol and interpretation criteria for curative surgery.

CASE PRESENTATION

We present the case of a 64-year-old woman with a large cystic parathyroid tumor and PHPT who experienced a significant delay in IOPTH decrease but was cured without additional surgery. The patient's basal intact PTH was 96.2 pg/mL, which decreased to 93.3 pg/mL at 25 min and 72.4 pg/mL at 55 min after removal of the parathyroid tumor. In an attempt to elucidate its pathophysiology, 1-84 PTH levels were measured in stored serum. These results can also be attributed to the relatively low basal PTH levels, intact PTH spike, and high ratio of large carboxyl-terminal PTH fragments present. The patient had normal intact PTH and calcium levels at the 9-month postoperative visit.

CONCLUSIONS

As detailed reports on these phenomena are scarce, we discuss the causes of false-negative IOPTH results in terms of PTH production, secretion, metabolism, and differences in measurement methods to avoid unnecessary surgery.

Diagnostic Accuracy of Intraoperative Intact Parathyroid Hormone Monitoring for Surgical Outcomes of Secondary Hyperparathyroidism

BACKGROUND Intraoperative intact parathyroid hormone (IO-iPTH) monitoring has not reached a consensus in predicting surgical outcomes of secondary hyperparathyroidism. Here, we explore the predictive effect of IO-iPTH monitoring on surgical outcomes of secondary hyperparathyroidism as a potentially effective standard. MATERIAL AND METHODS We enrolled 119 patients who underwent total parathyroidectomy with autotransplantation from January 2016 to August 2019. Intact parathyroid hormone (iPTH) levels were tested 1 day before surgery (iPTHpre), 10 min after glands resection (iPTH10min), and 1 and 7 days after the operation (iPTHd1, iPTHd7). According to iPTHpre levels, patients were divided into a <2000 pg/ml group and a ≥2000 pg/ml group, and the cutoff values were compared. In patients with successful parathyroidectomy, the value of iPTHpre minus iPTH10min (iPTHdec) and relative-iPTH10min were compared between groups. RESULTS Using cutoff values, the predictive criterion was defined as iPTH10min ≤314.5 pg/ml or relative-iPTH10min ≤12.4%. In the iPTHpre ≥2000 pg/ml group, iPTH10min had a higher predictive value (318 pg/ml vs 218 pg/ml) whereas relative-iPTH10min had a lower predictive value (12.1% vs 20.3%). In patients with successful PTX, the iPTHdec value of the iPTHpre ≥2000 pg/ml group was significantly higher than that of the <2000 pg/ml group. Additionally, the relative-iPTH10min was significantly lower in the ≥2000 pg/ml group than in the <2000 pg/ml group. CONCLUSIONS An intraoperative predictive criterion of iPTH10min ≤314.5 pg/ml or relative-iPTH10min ≤12.4% is associated with effectively predicting surgical success of secondary hyperparathyroidism. The predictive value is affected by iPTHpre level; therefore, a variable prediction standard based on iPTHpre levels shall be established.

Practice Patterns in Parathyroid Surgery: A Survey of Asia-Pacific Parathyroid Surgeons

BACKGROUND

Practice variations exist amongst parathyroid surgeons depending on their expertise and resources. Our study aims to elucidate the choice of surgical techniques and adjuncts used in parathyroid surgery by surgeons in the Asia-Pacific region.

METHODS

A 25-question online survey was sent to members of five endocrine surgery associations. Questions covered training background, practice environment and preferred techniques in parathyroid surgery. Respondents were divided into three regions: Australia/New Zealand, South/South East Asia and East Asia, and responses were analysed according to region, specialty, case volume and years in practice.

RESULTS

One hundred ninety-six surgeons returned the questionnaire. Most surgeons (98%) routinely perform preoperative imaging, with 75% preferring dual imaging with ^99mTcsestamibi and ultrasound. Ten per cent of surgeons use parathyroid 4DCT as first-line imaging, more commonly in East Asia (p = 0.038). Minimally invasive parathyroidectomy is the favoured technique of choice (97%). Most surgeons reporting robotic or endoscopic approaches are from East Asia. Rapid intraoperative parathyroid hormone is accessible to just under half of the surgeons but less available in Australian/New Zealand (p < 0.001). The use of intraoperative neuromonitoring is not commonly used, even less so amongst Asian surgeons (p = 0.048) and surgeons with low case load (p = 0.013).

CONCLUSION

Dual localisation techniques are the preferred choice of investigations in preparation for parathyroid surgery, with minimally invasive surgery without neuromonitoring the preferred approach. Use of adjuncts is sporadic and limited to certain centres.

A systematic evaluation of immunoassay point-of-care testing to define impact on patients' outcomes

Background Point-of-care testing has been developed to provide rapid test results. Most published studies focus on analytical performance, neglecting its impact on patient outcomes. Objective To review the analytical performance and accuracy of point-of-care testing specifically planned for immunoassay and to evaluate the impact of faster results on patient management. Methods A search of electronic databases for studies reporting immunoassay results obtained in both point-of-care testing and central laboratory scenarios was performed. Data were extracted concerning the study details, and the methodological quality was assessed. The analytical characteristics and diagnostic accuracy of six points-of-care testing: troponin, procalcitonin, parathyroid hormone, brain natriuretic peptide, C-reactive protein and neutrophil gelatinase-associated lipocalin were evaluated. Results A total of 116 scientific papers were analysed. Studies measuring procalcitonin, parathyroid hormone and neutrophil gelatinase-associated lipocalin reported a limited impact on diagnostic decisions. Seven studies measuring C-reactive protein claimed a significant reduction of antibiotic prescription. Several authors evaluated brain natriuretic peptide or troponin reporting faster decision-making without any improvement in clinical outcome. Forty-four per cent of studies reported analytical data, showing satisfactory correlations between results obtained through point-of-care testing and central laboratory setting. Half of studies defined the diagnostic accuracy of point-of-care testing as acceptable for troponin (median sensitivity and specificity: 74% and 94%, respectively), brain natriuretic peptide (median sensitivity and specificity: 82% and 88%, respectively) and C-reactive protein (median sensitivity and specificity 85%). Conclusions Point-of-care testing immunoassay results seem to be reliable and accurate for troponin, brain natriuretic peptide and C-reactive protein. The satisfactory analytical performance, together with an excellent practicability, suggests that it could be a consistent tool in clinical practice, but data are lacking regarding the patient outcomes.

Intraoperative PTH: Effect of sample timing and vitamin D status

Objective

To assess the effect of timing of intraoperative parathormone (iPTH) samples and 25-hydroxyvitamin D (25-OHD) status on decision-making during parathyroidectomy.

Methods

A total of 77 patients with primary hyperparathyroidism and iPTH levels (preincision, preremoval, 5 (T5) and 10 (T10) minutes postremoval) performed during parathyroidectomy were reviewed.

Results

Forty-one percent of patients were 25-OHD insufficient. We noted a significant correlation between preoperative 25-OHD and preincision iPTH ( P = 0.002) but not iPTH at postremoval levels (T5, P = 0.89; T10, P = 0.42). When compared with preincision iPTH, the use of either the higher preincision or preremoval iPTH baseline significantly improves the assay sensitivity from 83% to 93% at T5 ( P = 0.01) and 87% to 97% at T10 ( P = 0.02). Surgical cure was obtained in 98% of patients.

Conclusion

Obtaining preremoval iPTH allowed earlier decision with respect to operative completion in 38% of cases. 25-OHD status does not appear to significantly affect interpretation of iPTH levels.

Significance

Obtaining both baseline levels significantly improves sensitivity in iPTH monitoring. © 2007 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

Focused parathyroidectomy without intra-operative parathyroid hormone monitoring for primary hyperparathyroidism: results in a low-volume hospital

BACKGROUND

The role of routine intra-operative parathyroid hormone monitoring for sporadic primary hyperparathyroidism is contentious. Satisfactory results can be achieved in high-volume centres. The results of low-volume hospitals are rarely studied.

METHODS

A retrospective, non-comparative study was conducted. From November 2002 to October 2012, 105 patients with clinically sporadic primary hyperparathyroidism underwent focused parathyroidectomy without intra-operative parathyroid hormone monitoring. Single adenoma was localised on pre-operative ultrasonography or sestamibi scan. The cure rate, surgical complication rate and pathology findings were evaluated.

RESULTS

Most of the operations (63.8 per cent) were performed under local anaesthesia. All but two patients (98.1 per cent) were cured after surgery. There was only one case of double adenomas. No recurrent hyperparathyroidism was observed after a mean follow up of 56.9 months. Surgical complications comprised two cases (1.9 per cent) of transient vocal fold palsy and one case (1.0 per cent) of permanent vocal fold palsy. Seven patients (6.7 per cent) suffered temporary hypocalcaemia.

CONCLUSION

Satisfactory results of focused parathyroidectomy without routine intra-operative parathyroid hormone monitoring for appropriately selected primary hyperparathyroidism cases can be attained in a low-volume hospital.

Is intraoperative parathyroid hormone monitoring necessary with ipsilateral parathyroid gland visualization during anticipated unilateral exploration for primary hyperparathyroidism: a two-institution analysis of more than 2,000 patients

INTRODUCTION

Intraoperative parathyroid hormone (ioPTH) monitoring during focused parathyroidectomy for primary hyperparathyroidism (PHPT) is used commonly, but some argue that ioPTH adds little if a normal ipsilateral parathyroid gland (IPG) is visualized. This hypothesis was tested for validity.

METHODS

The prospective databases of consecutive patients with PHPT undergoing initial parathyroidectomy with ioPTH at two academic institutions were queried. Patients with ectopic adenoma, familial PHPT, previous parathyroidectomy, planned bilateral exploration, or <6 months follow-up were excluded. Persistence was defined as hypercalcemia at <6 months.

RESULTS

From 1998 to 2013, 2,162 patients met inclusion criteria, and the rate of persistent disease was 1.5%. Most (n = 1,353; 63.5%) underwent single-gland resection with ioPTH and no IPG visualization, with 1% persistence. Among patients with a single adenoma resected and a normal IPG visualized, 15.2% had contralateral disease. Resection based on IPG appearance alone would have resulted in 13% persistent disease.

CONCLUSION

In PHPT, the cure rate for initial unilateral exploration guided by ioPTH is 98.5% versus a predicted rate of 87% when decision making is based on IPG appearance alone. Routine visualization of IPG is not necessary during exploration for suspected single adenoma guided by ioPTH. ioPTH remains useful in optimizing outcomes.

Point-of-care testing: where is the evidence? A systematic survey

Point-of-care testing (POCT) has had rapid technological development and their use is widespread in clinical laboratories to assure reduction of turn-around-time and rapid patient management in some clinical settings where it is important to make quick decisions. Until now the papers published about the POCT have focused on the reliability of the technology used and their analytical accuracy. We aim to perform a systematic survey of the evidence of POCT efficacy focused on clinical outcomes, selecting POCT denoted special analytes characterized by possible high clinical impact. We searched in Medline and Embase. Two independent reviewers assessed the eligibility, extracted study details and assessed the methodological quality of studies. We analyzed 84 studies for five POCT instruments: neonatal bilirubin, procalcitonin, intra-operative parathyroid hormone, troponin and blood gas analysis. Studies were at high risk of bias. Most of the papers (50%) were studies of correlation between the results obtained by using POCT instruments and those obtained by using laboratory instruments. These data showed a satisfactory correlation between methods when similar analytical reactions were used. Only 13% of the studies evaluated the impact of POCT on clinical practice. POCT decreases the time elapsed for making decisions on patient management but the clinical outcomes have never been adequately evaluated. Our work shows that, although POCT has the potential to provide beneficial patient outcome, further studies may be required, especially for defining its real utility on clinical decision making.

Gamma Probe Guided Minimally Invasive Parathyroidectomy without Quick Parathyroid Hormone Measurement in the Cases of Solitary Parathyroid Adenomas

OBJECTIVE

In this study, our aim was to study the efficiency of gamma probe guided minimally invasive parathyroidectomy (GP-MIP), conducted without the intra-operative quick parathyroid hormone (QPTH) measurement in the cases of solitary parathyroid adenomas (SPA) detected with USG and dual phase 99mTc-MIBI parathyroid scintigraphy (PS) in the preoperative period.

MATERIAL AND METHODS

This clinical study was performed in 31 SPA patients (27 female, 4 male; mean age 51±11years) between February 2006 and January 2009. All patients were operated within 30 days after the detection of the SPA with dual phase 99mTc-MIBI PS and USG. The GP-MIP was done 90-120 min after the iv injection of 740 MBq 99mTc-MIBI. In all cases, except 1 patient, the GP-MIP was performed under local anesthesia; due to the enormity of size of SPA, then general anesthesia is chosen.

RESULTS

The operation time was 30-60 min, mean 38,2±7 min. In the first postoperative day, there was a more than 50% decrease in PTH levels in all patients and all but one had normal serum calcium levels. Transient hypocalcemia was detected in one patient.

CONCLUSION

GP-MIP without intra-operative QPTH measurement is a suitable method in the surgical treatment of SPA detected by dual phase 99mTc-MIBI PS and USG.

CONFLICT OF INTEREST

None declared.

Feasibility of rapid parathormone assay for enabling minimally invasive parathyroid excision

There is no doubt that the success of minimally invasive parathyroidectomy (MIP) has changed the whole treatment of patients with primary hyperparathyroidism, especially the approach towards traditional bilateral neck exploration. A single adenoma is the most common cause of primary hyperparathyroidism and its removal results in cure. Hence, it is worth the effort to localise and excise the single adenoma using modern technologies such as high-quality sestamibi scans and to confirm complete excision using rapid intra operative parathormone (IOPTH) assays. The objective of the study was to evaluate the feasibility of rapid IOPTH assay in successfully facilitating minimally invasive parathyroid excision. This research involved the retrospective study of seven patients, who underwent MIP at Sagar Hospital in Bengaluru, India, for parathyroid adenoma. All patients with evidence of unifocal disease on sestamibi scanning and cervical ultrasonography, underwent MIP via 2-3 cm lateral incision. Blood samples for measurement of IOPTH were taken at the time of induction of anaesthesia and 10 min after the adenoma excision. Reduction of parathormone (PTH) levels of more than 50 % in the postexcision sample was taken as evidence for complete extirpation of parathyroid adenoma. A solitary adenoma was identified in all the seven patients. After MIP, IOPTH levels fell in six of the seven patients. Following the surgery, all the cases were followed up for a period of 1 month. During this time, except for one patient, six patients remained asymptomatic and blood tests revealed normal serum calcium levels. A histopathological examination confirmed the diagnosis of parathyroid adenoma in six of the seven patients. After accurate preoperative localisation of the adenoma in patients with primary hyperparathyroidism, MIP with IOPTH measurement offers a safe and successful outcome.

Intraoperative parathyroid hormone concentration to confirm removal of hypersecretory parathyroid tissue and time to postoperative normocalcaemia in nine dogs with primary hyperparathyroidism

OBJECTIVE

To determine (1) whether the intraoperative parathyroid hormone concentration ([PTH]) during parathyroidectomy (PTX) can be used to indicate cure in dogs with primary hyperparathyroidism and (2) the time taken for postoperative serum calcium concentration to normalise.

DESIGN

Retrospective study (2005-10) from a private referral hospital in Sydney, New South Wales, Australia.

PROCEDURE

Nine client-owned dogs underwent surgical PTX for naturally occurring primary hyperparathyroidism. [PTH] was measured from serum samples taken immediately post-induction (pre-PTX]) and at least 20 min after adenoma removal (post-PTX) for all dogs, and during parathyroid gland manipulation (intra-PTX) for six dogs. The concentration of ionised calcium (iCa) was measured at various time points postoperatively until it normalised, then stabilised or decreased below reference ranges. Statistical analysis compared the mean pre-, intra- and post-PTX [PTH] and the average rate of decline of iCa concentration postoperatively.

RESULTS

All dogs demonstrated a significant decrease from mean pre-PTX [PTH] (168.51 pg/mL) to mean post-PTX [PTH] (29.20 pg/mL). There was a significant increase in mean intra-PTX [PTH] (279.78 pg/mL). The average rate of decline of iCa concentration postoperatively to within the reference range (1.12-1.40 mmol/L) occurred after 24 h.

CONCLUSION

Intraoperative measurements of [PTH] can be used clinically to determine cure of primary hyperparathyroidism. Parathyroid hormone increases significantly during parathyroid gland manipulation. Plasma iCa concentration returns to within the reference range on average 24 h after successful PTX. Not all dogs require vitamin D or calcium supplementation pre- or postoperatively.

Simplified minimally invasive parathyroidectomy: a series of 100 cases and review of the literature

INTRODUCTION

Conventional practice of parathyroidectomy has been collar incision with bilateral neck exploration and a four-gland evaluation. Our local practice involves simplified parathyroidectomy via mini-incision without routine use of intraoperative adjuncts. The aim of this study is to demonstrate that a good success rate can be achieved, which will hopefully encourage more to undertake minimally invasive parathyroid surgery.

MATERIALS AND METHODS

A prospective case series of the first 100 patients undergoing minimally invasive parathyroidectomy (MIP) by a single surgeon at a single institution were included. Preoperatively, patients underwent ultrasonography (US) and/or a sestamibi (MIBI) scan for localisation. Parathyroidectomy was performed following an algorithm of intraoperative decisions. Serum calcium and/or parathyroid hormone levels were checked at follow-up. Postoperative normocalcaemia was considered success independent of serum parathyroid hormone levels

RESULTS

The patients had a median age of 63 years. Of the 100 patients, 83 were female and 17 male. Seven patients had a conversion to bilateral exploration. The mean operative time for unilateral and bilateral exploration was 42.38 minutes and 76.43 minutes respectively. Separately, a MIBI scan and US lateralised the side of the lesion in 82.8% and 79.5% of cases respectively. When US and the MIBI scan agreed, the predictive accuracy of the side of the lesion was 87.5%. The majority of patients (96%) had a successful return to normocalcaemia. No complications were encountered.

CONCLUSIONS

Excellent results are achievable with simplified MIP even without intraoperative adjuncts. Preoperative localisation is helpful in determining the side of incision. Our technique demonstrates a key principle of surgery: to keep things simple.

Bilateral neck exploration in primary hyperparathyroidism--when is it selected and how is it performed?

BACKGROUND

Although most patients with primary hyperparathyroidism (PHPT) are ideal candidates for minimally invasive parathyroidectomy, some will have more than one enlarged gland and require bilateral neck exploration to achieve biochemical cure. We evaluated the clinical evidence for when to choose bilateral neck exploration for patients with PHPT.

METHODS

We searched PubMed for English-language studies published from 1996 to 2008. The level of clinical evidence was determined according to the criteria proposed by Sackett (Chest 95[2 Suppl]:2S, 1989), and the grade of recommendation was established according to the criteria proposed by Heinrich et al. (Ann Surg 243:154, 2006).

RESULTS

Level III-IV evidence shows that patients with multiple endocrine neoplasia (MEN) 1 and PHPT should have a bilateral neck exploration (grade C recommendation). Only level IV evidence indicates that patients with familial PHPT should do so (no recommendation). Although most patients with MEN 2A have single-gland disease, bilateral neck exploration is still indicated, because they will have either a therapeutic or prophylactic total thyroidectomy for medullary thyroid cancer. A history of head and neck irradiation is associated with PHPT, but the risk of multi-gland parathyroid disease is apparently no higher than in sporadic cases (level IV evidence, no recommendation). Previous or current lithium therapy confers a higher risk of multi-gland disease (25%-45%; level IV-V evidence), which may require bilateral neck exploration. Preoperative localizing studies reliably identify most patients with single-gland but not multi-gland disease (level II-IV evidence). Negative localizing studies confer an approximately 50% risk of multi-gland disease and indicate that bilateral neck exploration is necessary. If two localizing studies are concordant, few patients will require bilateral neck exploration (level IV, no recommendation).

CONCLUSIONS

No level I or II evidence reliably identifies preoperative clinical risk factors for determining which patients should have routine bilateral neck exploration for multi-gland disease or for intraoperative decision making to convert to bilateral neck exploration. Imaging studies are positive in most patients (level II). No randomized studies exist to determine when a bilateral neck exploration is indicated based on clinical risk factors or imaging studies that may suggest multi-gland disease.

Intraoperative PTH Assay during Minimally Invasive Parathyroidectomy May Be Helpful in the Detection of Double Adenomas and May Minimise the Risk of Recurrent Surgery

Background. Minimally invasive parathyroidectomy (MIP) is increasingly replacing the traditional bilateral neck exploration in the treatment of primary hyperparathyroidism (PHP). Intraoperative PTH (IOPTH) measurement has recently been introduced as a useful adjunct in confirming successful excision of abnormal parathyroid gland. Aims. We evaluate the safety, efficacy, and clinical usefulness of IOPTH measurement during MIP in a district general hospital. Methods. Retrospective review of eleven consecutive patients with PHP who underwent MIP with IOPTH, following preoperative assessment with ultrasound and sestamibi scans. Results. All patients had successful removal of the abnormal parathyroid gland. The concordance rate between ultrasound and sestamibi scan in localising the parathyroid adenoma was 82%. IOPTH measurement confirmed the removal of adenoma in all cases and, in one case, led to identification of a second adenoma, not localised preoperatively. The median hospital stay was 2 days (range 1-7 days). All patients remained normocalcaemic after a median of 6 months (range 1-10 months). Conclusions. Minimally invasive parathyroidectomy is a feasible, safe, and effective method for treatment of PHP. The use of IOPTH monitoring potentially offers increased sensitivity in detecting multiglandular disease, can minimise the need and risk associated with recurrent operations, and may facilitate cost-effective minimally invasive surgery.

The value of intraoperative parathyroid hormone monitoring in localized primary hyperparathyroidism: a cost analysis

Background

Minimally invasive parathyroidectomy (MIP) is the preferred approach to primary hyperparathyroidism (PHPT) when a single adenoma can be localized preoperatively. The added value of intraoperative parathyroid hormone (IOPTH) monitoring remains debated because its ability to prevent failed parathyroidectomy due to unrecognized multiple gland disease (MGD) must be balanced against assay-related costs. We used a decision tree and cost analysis model to examine IOPTH monitoring in localized PHPT.

Methods

Literature review identified 17 studies involving 4,280 unique patients, permitting estimation of base case costs and probabilities. Sensitivity analyses were performed to evaluate the uncertainty of the assumptions associated with IOPTH monitoring and surgical outcomes. IOPTH cost, MGD rate, and reoperation cost were varied to evaluate potential cost savings from IOPTH.

Results

The base case assumption was that in well-localized PHPT, IOPTH monitoring would increase the success rate of MIP from 96.3 to 98.8%. The cost of IOPTH varied with operating room time used. IOPTH reduced overall treatment costs only when total assay-related costs fell below $110 per case. Inaccurate localization and high reoperation cost both independently increased the value of IOPTH monitoring. The IOPTH strategy was cost saving when the rate of unrecognized MGD exceeded 6% or if the cost of reoperation exceeded $12,000 (compared with initial MIP cost of $3733). Setting the positive predictive value of IOPTH at 100% and reducing the false-negative rate to 0% did not substantially alter these findings.

Conclusions

Institution-specific factors influence the value of IOPTH. In this model, IOPTH increased the cure rate marginally while incurring approximately 4% additional cost.

Intraoperative adjuncts in surgery for primary hyperparathyroidism

PURPOSE

This paper is a review of the evidence base to produce recommendations for the use of intraoperative parathyroid hormone (PTH), radioguided parathyroidectomy (RGP), methylene blue (MB), frozen section, and intraoperative neuromonitoring during surgery for primary hyperparathyroidism (PHPT).

MATERIALS AND METHODS

A Medline keyword search of English-language articles led to the production of a draft document, subsequently revised by committee, containing levels of evidence and the grading of recommendations as proposed by the Agency for Healthcare Research and Quality.

RESULTS

Literature review provides the basis for clear recommendations on the use of intraoperative PTH at surgery for PHPT. There is little evidence to support the use of RGP, MB, routine frozen section, and intraoperative neuromonitoring.

99MTc-sestamibi as sole technique in selection of primary hyperparathyroidism patients for unilateral neck exploration

BACKGROUND

Unilateral neck exploration (UNE) is becoming the procedure of choice for treatment of primary hyperparathyroidism (PHPT). The aim of this study was to evaluate the role of (99m)Tc-sestamibi (MIBI) parathyroid scintigraphy as the sole technique in selecting patients for UNE.

METHOD

We selected 136 consecutive PHPT patients who had only 1 solitary uptake at a MIBI were for UNE. The technique was a single dual-phase using MIBI and a subtraction technique with (99m)Tc-pertechnetate. Imaging data were correlated with surgical results.

RESULTS

In 3 cases, the sestamibi scan was falsely positive, 1 had a contralateral location relative to the uptake, and 2 had multiglandular hyperplasia. Overall, the positive predictive value (PPV) of MIBI for detecting a solitary parathyroid adenoma in patients with 1 solitary uptake was 97.8. Sixteen patients (12%) had evidence of multinodular goiter. Overall, the PPV of MIBI was 98.4% (2 false positive among 120 cases) in patients with no multinodular thyroid disease (MNG) and 93.7% (1 false negative among 16 cases) in patients with MNG. The mean duration of the surgical procedure was 34.17 minutes. Mean hospitalization was 0.6 days. Conversion to bilateral neck exploration was performed in 5 patients. After a period of follow-up of 40 months (range, 6-72 months), the cure rate was 98%.

CONCLUSION

Patients with PHPT and unequivocally positive preoperative (99m)Tc-sestamibi can safely be managed with UNE without additional localizing techniques.

Does histopathology predict parathyroid hypersecretion and influence correctly the extent of parathyroidectomy in patients with sporadic primary hyperparathyroidism?

BACKGROUND

Parathyroid histopathology has been used to predict single or multiglandular disease (MGD). "Hyperplasia" implies MGD, whereas "adenoma" suggests single gland involvement. Intraoperative parathyroid hormone (PTH) monitoring (IPM) guides parathyroidectomy based on function. We sought to evaluate the accuracy of histopathology in the diagnosis of single or MGD and in predicting operative success.

METHODS

We reexamined the parathyroid glands from 402 patients with sporadic primary hyperparathyroidism (SPHPT) who underwent initial IPM-guided parathyroidectomies. Operative findings and outcome were correlated with histopathology of excised glands. Operative success was eucalcemia for >or=6 months and recurrence of hypercalcemia/high PTH after successful parathyroidectomy.

RESULTS

Of 402 patients, 384 had 1 gland excised resulting in operative success; hyperplasia was diagnosed in 244 of the 384 (64%), with only 2 developing recurrence. Of the 384 patients, 140 (37%) had adenomas with 1 late recurrence. There were 18 patients with MGD (14 hyperplasias, 4 adenomas). There were 5 failures with hyperplasia predicting MGD. Histopathology was incorrect in predicting the number of glands involved in 249 of 402 (62%) patients, and IPM was incorrect in only 13 (3%).

CONCLUSION

Histopathology of excised abnormal parathyroid glands does not predict the secretory function of the remaining parathyroid glands left in situ. IPM guided parathyroidectomy accurately based on function alone; however, histopathology was inaccurate in predicting MGD and should not be used to guide parathyroidectomy in patients with SPHPT.

Minimally invasive parathyroidectomy using the lateral focused mini-incision technique without intraoperative parathyroid hormone monitoring

BACKGROUND

Minimally invasive parathyroidectomy (MIP) involves scan-directed removal of a single adenoma through a 2.0-cm mini-incision without intraoperative monitoring. The aim of this study was to analyse the outcomes of MIP using such a simplified technique.

METHODS

The study group comprised 500 consecutive patients undergoing MIP via a lateral mini-incision from August 2000 to September 2005. Levels of parathyroid hormone (PTH) were measured after operation solely to aid informed discharge.

RESULTS

Some 97.4 per cent of patients were initially cured by MIP. Eight patients remained hypercalcaemic and a further five were normocalcaemic on the day after surgery but became hypercalcaemic again within 3 months of the procedure. Eleven of these patients were cured with subsequent re-exploration. Analysis of postoperative PTH data indicated that, at best, the use of intraoperative PTH measurement during surgery would have increased the cure rate by only a further 1 per cent. Three (0.6 per cent) of 500 patients had permanent recurrent laryngeal nerve palsy after MIP.

CONCLUSION

MIP performed by the lateral focused mini-incision technique, without the use of intraoperative PTH monitoring, is a safe and effective procedure that results in outcomes equal to those of bilateral neck exploration.

Experienced Radio-Guided Surgery Teams Can Successfully Perform Minimally Invasive Radio-Guided Parathyroidectomy without Intraoperative Parathyroid Hormone Assays

Minimally invasive parathyroidectomy is an accepted treatment option for primary hyperpara-thyroidism. The need for intraoperative parathyroid hormone assays (iPTH) to confirm adenoma removal remains controversial. We studied minimally invasive radio-guided parathyroidectomy (MIRP) performed using preoperative sestamibi localization studies, intraoperative gamma detection probe, and the selective use of frozen section pathology without the use of iPTH. This is a single institution review of patients with primary hyperparathyroidism treated with MIRP by surgeons experienced in radio-guided surgery between October 1, 1998 and July 15, 2005. Information was obtained by reviewing computer medical records as well as contacting primary care physicians. Factors evaluated included laboratory values, pathology results, and evidence of recurrence. One hundred forty patients were included with a median preoperative calcium level of 11.3 mg/dL (range, 9.6–17) and a PTH level of 147 pg/mL (range, 19–5042). The median postoperative calcium level was 9.3 mg/dL. All patients were initially eucalcemic postoperatively except for one who had normal parathyroid levels. However, five (4%) patients required re-exploration for various reasons. Of the failures, one was secondary to the development of secondary hyperparathyroidism, and therefore would not have benefited from iPTH, one had thyroid tissue removed at the first operation, and three developed evidence of a second adenoma. One of these three patients had a drop in PTH level from 1558 pg/mL preoperatively to 64 pg/mL on postoperative Day 1, indicating that iPTH would not have prevented this failure. Thus, only three (2.1%) patients could have potentially benefited from the use of iPTH. MIRP was successful in 96 per cent of patients using a combination of preoperative sestamibi scans, intraoperative localization with a gamma probe, and the selective use of frozen pathology. This correlates with reported success rates of 95 per cent to 100 per cent using iPTH. We conclude that minimally invasive parathyroidectomy can be successfully performed without using iPTH assays.

Intraoperative parathyroid hormone measurement during minimally invasive parathyroidectomy: does it "value-add" to decision-making?

BACKGROUND

Routine use of intraoperative parathyroid hormone levels (IOPTH) during minimally invasive parathyroidectomy (MIP) has been challenged simply because the test works best when needed least, ie, once a solitary adenoma has been resected, and is less accurate with multiple gland disease. It has also been shown not to be cost-effective. The aim of this study was to determine if IOPTH "value-added" to decision-making during MIP.

STUDY DESIGN

The study group comprised 100 consecutive patients with sporadic hyperparathyroidism and an unequivocally positive sestamibi scan who were undergoing MIP in our unit from June 2004 until October 2005, from whom blood was collected for parathyroid hormone measurement preoperatively, preexcision, and at 10 and 30 minutes postremoval. No action was taken on the results of the test.

RESULTS

Ninety-eight patients were cured by MIP alone. Two patients had persistent hyperparathyroidism, one of whom was cured with subsequent open reexploration and removal of a second adenoma, and the other remains hypercalcemic despite additional open neck exploration. IOPTH in both patients failed to fall in retrospect, only the first would have been cured by conversion at the time of operation. The value-added accuracy of IOPTH was really only 1%. In an additional nine patients, IOPTH at 10 minutes had failed to fall by > 50% from the highest level, those patients (9%) would have been subjected to an unnecessary conversion on the basis of a false-negative result.

CONCLUSIONS

IOPTH does not substantially value-add to decision-making during MIP. Most patients will be cured with appropriate selection for MIP based on preoperative localization studies.

Successful minimally invasive parathyroidectomy for primary hyperparathyroidism without using intraoperative parathyroid hormone assays

BACKGROUND

The need for intraoperative parathyroid hormone (iPTH) assays in minimally invasive parathyroidectomy (MIP) remains controversial. We report the results of MIP performed without the use of iPTH assays.

METHODS

This was a single-institution retrospective review of patients with primary hyperparathyroidism treated with MIP between October 1, 1998, and December 31, 2002.

RESULTS

Seventy-seven patients were studied. The mean preoperative calcium level was 11.4 mg/dL. All patients had a normal calcium level postoperatively (range, 7.4-10.2 mg/dL, mean, 9.1 mg/dL). Three patients (4%) required re-exploration for various reasons including the development of a second adenoma, secondary hyperparathyroidism, and discordant pathology. All 3 patients initially were eucalcemic.

CONCLUSIONS

Our success rate of 96% using a combination of preoperative sestamibi scans, intraoperative gamma probe localization, and selective frozen pathology is consistent with the published success rates using iPTH assays of 95% to 100%. We conclude that MIP can be performed successfully without using iPTH assays.

Are frozen sections useful and cost-effective in the era of intraoperative qPTH assays?

BACKGROUND

Since intraoperative quick parathormone (IOqPTH) assays are available, the role of frozen sections (FS) during parathyroid exploration has become questionable. This study compares the results of FS and IOqPTH in primary hyperparathyroidism (pHPT).

METHODS

FS and IOqPTH assays were performed in 102 patients who underwent bilateral neck explorations or targeted parathyroidectomy for pHPT. The operation was considered complete when both an IOqPTH drop >50% and a FS diagnosis of parathyroid adenoma were obtained.

RESULTS

Cure was achieved in all patients. Potential pitfalls for successful operation were encountered in 14 patients with multiglandular diseases and in 4 patients who had nonparathyroid tissue removed. FS correctly predicted the definitive histologic diagnosis with an accuracy of 81%. FS failures potentially misguided the operative therapy in 19% (14 insufficient explorations and 5 unnecessarily prolonged explorations), while IOqPTH identified all potential pitfalls and correctly guided the operative strategy, suggesting further exploration, in 100% of cases (P < .0001). After bilateral neck exploration, FS and IOqPTH correctly guided operative strategy in 86% and 100% of cases, respectively (P < .05), but both techniques were never indispensable, because potential pitfalls were already evident by macroscopic intraoperative appearance. The turnaround time and costs for IOqPTH were lower (P < .001).

CONCLUSIONS

The role of FS should be reconsidered, since it can misguide the operative strategy. IOqPTH is indispensable for a focused approach and, although unnecessary in bilateral neck exploration, is more useful and cost-effective than FS.

A systematic review of the diagnosis and treatment of primary hyperparathyroidism from 1995 to 2003

OBJECTIVE

To systematically review the current preoperative diagnostic modalities, surgical treatments, and glandular pathologies associated with primary hyperparathyroidism.

STUDY DESIGN

A systematic literature review.

RESULTS

Of the 20,225 cases of primary hyperparathyroidism reported, solitary adenomas (SA), multiple gland hyperplasia disease (MGHD), double adenomas (DA), and parathyroid carcinomas (CAR) occurred in 88.90%, 5.74%, 4.14%, and 0.74% of cases respectively. Tc 99m -sestamibi and ultrasound were 88.44% and 78.55% sensitive, respectively, for SA, 44.46% and 34.86% for MGHD, and 29.95% and 16.20% for DA, respectively. Postoperative normocalcemia was achieved in 96.66%, 95.25%, and 97.69% of patients offered minimally invasive radio-guided parathyroidectomy (MIRP), unilateral, and bilateral neck exploration (BNE). Intraoperative PTH assays (IOPTH) were helpful in approximately 60% of bilateral neck exploration conversion (BNEC) surgeries.

CONCLUSION

The overall prevalence of multiple gland disease (MGD and DA) was lower than often suggested by conventional wisdom. Furthermore, preoperative imaging was less accurate than it is often perceived for accurately imaging MGD. MIRP and UNE were more successful in achieving normocalcemia than is typically quoted. IOPTH was a helpful but not "fool-proof" adjunct in parathyroid exploration surgery.

SIGNIFICANCE

These results support a greater role for the treatment of primary hyperparathyroidism using less invasive approaches. EMB rating: B-3.

Surgical management of primary hyperparathyroidism: the case for giving up quick intraoperative PTH assay in favor of routine PTH measurement the morning after

OBJECTIVE

To analyze the utility of quick intraoperative parathyroid hormone (PTH) measurement in the surgical management of primary hyperparathyroidism.

BACKGROUND DATA

The use of intraoperative PTH monitoring is well established in the surgery of primary hyperparathyroidism. However, some false-negative predictions lead to unnecessary explorations; furthermore, surgeons are becoming increasingly dependent on hormone measurement for intraoperative decisions, which raises concerns about the cost-effectiveness of the method.

METHODS

A retrospective analysis of 268 neck explorations performed for primary hyperparathyroidism using intraoperative PTH monitoring from April 2001 to February 2003 was done. We used the criterion of "biologic recovery" of hyperfunctioning tissue, defined as a more than 50% decrease in PTH level from baseline value at 5 minutes after excision to predict the outcome of successful parathyroidectomy documented by normal postoperative serum calcium level. Additionally, we also sampled PTH at 10 minutes, 30 minutes, and the morning after surgery to compare the predictive value of delayed sampling. Patients were classified according to the prediction being concordant or discordant with the outcome. The data were analyzed using a 2 x 2 table construct for each of the sampling times, therefore providing sequential sensitivity, specificity, positive and negative predictive values, and overall accuracy of the predictions.

RESULTS

Concordance or overall accuracy of prediction (true positives and negatives) was obtained in 229 cases (85.4%), and discordance or failure of prediction (false positives and negatives) was obtained in 34 cases (12.7%) at T5. On analyzing the iPTH prediction at T10, T30, and D1 among the group of 33 false negatives, we found that 28 (10.4%) patients reached the concordance at 30 minutes, while by the first day 32 patients (12.3%) had achieved concordance. Thus, there was a progressive increase in sensitivity and overall accuracy, but more importantly, in the negative predictive value reaching 88.9% on the day after surgery.

CONCLUSIONS

The method of sampling PTH intraoperatively at 5 minutes has a high positive predictive value (99.5%) but a low negative predictive value (19.5%), which can lead to unnecessary explorations and a delay in the operative procedure. The negative predictive value increases substantially at 30 minutes and is best on the day after surgery. We suggest giving up the intraoperative measurement of PTH to adopt the first day postoperative measurement of PTH as a predictor of successful parathyroidectomy.

Quick intraoperative parathyroid hormone assay: surgical adjunct to allow limited parathyroidectomy, improve success rate, and predict outcome

Intraoperative parathyroid hormone (PTH) assay (QPTH) has made possible less invasive operative approaches in the treatment of primary hyperparathyroidism with stated advantages. When compared to the traditional bilateral neck exploration (BNE), only the targeted, hypersecreting gland is excised, leaving in situ non-visualized but normally functioning parathyroids. The QPTH-guided limited parathyroidectomy (LPX) must be able to identify multiglandular disease (MGD), predict a successful outcome, and have a low recurrence rate. In our series, 421 patients who underwent LPX were compared to 340 undergoing BNE; all operative failures and patients followed for 6 months or longer were included. Operative failure occurred if serum calcium and PTH levels were elevated within 6 months of parathyroidectomy. Multiglandular disease was defined in the LPX group as more than one gland excision guided by QPTH or operative failure after removal of a single abnormal gland; in the BNE group it was defined as excision of more than one enlarged gland. Recurrence was defined as elevated calcium and PTH after 6 months of eucalcemia. Operative failure and MGD rates were compared using chi-squared analysis. The method of Kaplan-Meier and the log-rank test were used to compare recurrence rates. Operative success was seen in 97% of LPX patients and in 94% of the BNE group ( p = 0.02). Multiglandular disease was identified in 3% of LPX patients and 10% of BNE patients ( p < 0.001). There was no statistical difference in the overall recurrence rates ( p = 0.23). The QPTH-guided parathyroidectomy identifies MGD and allows an improved success rate with the same low recurrence rate when compared to the results of BNE.

Unilateral surgery for hyperparathyroidism: indications, limits, and late results--new philosophy or expensive selection without improvement of surgical results?

We assessed the "late" results after unilateral parathyroidectomy (PTX) performed for selected indications. From October 1998 throughout March 2001 we operated on 454 patients for hyperparathyroidism (HPT). A positive unifocal (99m)tc-MIBI scan was required for the unilateral approach to be used. Intact parathormone (PTH) measurements were done intraoperatively. Postoperative calcium and PTH serum levels of unilaterally operated patients were checked. Follow-up has been 16.2 months (range 6-40 months). Of the 454 patients, 336 (74.0%) were not eligible for the unilateral approach; and 125 (27.5%) of the 454 patients had renal HPT. Among the 329 patients with primary HPT, 125 (38.0%) were excluded for well established reasons, and in 77 other cases (23.5%) preoperative imaging results did not allow the unilateral approach. Altogether, 126 patients (38.3%) with primary HPT were selected for the unilateral approach. Of the 126 unilateral operations, 8 (6.3%) had to be converted to a bilateral procedure. Among the 118 patients with a unilateral approach, 3 patients have been reoperated for overlooked contralateral disease, and 13 dropped out of the study. A total of 102 postoperative calcium and PTH serum late levels are known: 90 (88.2%) patients had normal levels; 10 (9.8%) had a high PTH level, and 2 (1.9%) had high ionized calcium levels. The failure rate in selected cases was 4.2% (5/118) (three were reoperated, and two had a supranormal postoperative ionized Ca level). Even with stringent indications, the late results of unilateral surgery (95.8% cure rate) barely matched those of conventional bilateral surgery (97.6% cure rate). The economic impact of such a surgical strategy should be clarified.

Intraoperative rapid parathyroid hormone monitoring in parathyroid surgery

The approach to parathyroid surgery has changed from bilateral exploration to focused, minimally invasive surgery. The intraoperative rapid parathyroid hormone assay has become an important tool in modern parathyroid surgery. This article outlines the technique and interpretation of the assay. Results of studies that evaluate the validity of the technique are summarized. The limitations and pitfalls of this technique are also discussed.

Minimal-access/minimally invasive parathyroidectomy for primary hyperparathyroidism

Minimal-access or minimally invasive parathyroidectomy is replacing a bilateral neck exploration as the surgical approach of choice in primary hyperparathyroidism (pHPT). When a parathyroid adenoma is localized preoperatively, ideally with sestamibi combined with ultrasonography, results equivalent to a bilateral neck exploration can be achieved through an incision less than 2.5 cm. Minimal-access techniques offer the advantage of cure under local anesthesia with a smaller incision and no overnight stay. Intraoperative measurement of parathyroid hormone (PTH) may be a valuable adjunct to confirmation of parathyroid adenoma removal, but currently appears to add little when preoperative localization is optimized. Controlled studies and long-term follow-up will be required to establish the true value of parathyroid minimal-access surgery.

Prospective evaluation of ultrasonography plus MIBI scintigraphy in selecting patients with primary hyperparathyroidism for unilateral neck exploration under local anaesthesia

BACKGROUND

Unilateral neck exploration (UNE) is currently replacing conventional bilateral neck exploration with cervicotomy for the surgical treatment of primary hyperparathyroidism (PHPT). However, many concerns still exist about the indications and the effectiveness of this minimally invasive approach.

METHODS

Prospective evaluation of operative results in consecutive patients having indications for UNE on the basis of strict selection criteria consisting of ultrasound-MIBI agreement in adenoma localization, absence of thyroid disease, and psychological suitability for undergoing a procedure under local anesthesia. No intraoperative confirmation study was adopted.

RESULTS

Among 149 consecutive PHPT patients, 45 (30.2%) had indications for UNE. No operative morbidity or mortality was observed. Mean operative time for the UNE procedure was 42 minutes (range 25 to 57). Conversion to general anesthesia was chosen for 5 patients (11.1%), whereas conversion to bilateral neck exploration was chosen for 3 patients (6.6%). For the UNE procedure, the success rate was as high as 91.7%. When the only factor indicated UNE, ultrasound-MIBI localization agreement had low sensibility (44.1%) and specificity (55.6%) but a high positive predictive value (91.1%).

CONCLUSIONS

We concluded that UNE performed under local anesthesia, without intraoperative confirmation studies, could be considered a safe and effective approach to treating patients with PHPT, but we regret the low rate of patients selected for this procedure because of the low sensitivity of the imaging-inclusion criterion.

Comparison of intraoperative iPTH assay (QPTH) criteria in guiding parathyroidectomy: which criterion is the most accurate?

BACKGROUND

The quick parathyroid hormone assay (QPTH) reliably measures intact parathyroid hormone (iPTH) levels intraoperatively. The accuracy in predicting postoperative calcemia is related to blood sample timing and the criteria applied. To improve specificity or to decrease the cost of QPTH, several criteria have been used to predict complete excision. This study compares the Miami criterion with other published QPTH criteria in predicting operative outcome.

METHODS

QPTH and the Miami criterion (iPTH drop > or =50% from the highest of either preincision or pre-excision level at 10 minutes after gland excision), were used to predict postoperative calcium levels of 341 consecutive patients with sporadic primary hyperparathyroidism who were followed > or =6 months after the operation or recognized as operative failures. Intraoperative iPTH values of these patients were reanalyzed with the use of 5 published criteria to predict complete resection. Postoperative calcium levels were correlated with criteria predictions.

RESULTS

Miami criterion correctly predicted postoperative calcium levels in 329 of 341 patients and was incorrect in 12 (3 false positives, 9 false negatives). With the use of other criteria, 2 of the 3 false-positive results would be prevented, but the 3% rate of false-negative predictions would increase to between 6% and 24%, causing unnecessary neck explorations to search for multiglandular disease.

CONCLUSIONS

Surgeons trying to increase QPTH specificity significantly decrease the accuracy and intraoperative usefulness of the assay. The Miami criterion has the highest accuracy when compared with other criteria.

Intraoperative testing for parathyroid hormone: a comprehensive review of the use of the assay and the relevant literature

OBJECTIVE

The rapid intraoperative parathyroid hormone assay is transforming the parathyroidectomy procedure. We present a review of the literature on the use of the assay as an adjunct to surgery. To our knowledge, this is the first review of the literature to encompass and compare all known primary studies of this assay in parathyroidectomy patients.

DATA SOURCES

Articles were collected by searching MEDLINE databases using relevant terminology. The references of these articles were reviewed for additional studies. Supplementary articles pertinent to the parathyroidectomy procedure, preoperative parathyroid localization studies, and intraoperative parathyroid hormone assay development also were examined.

STUDY SELECTION AND DATA EXTRACTION

One hundred sixty-five references were analyzed and categorized separately into groups.

DATA SYNTHESIS

The primary studies of intraoperative data on patients undergoing parathyroidectomy were compared when possible. Studies were analyzed by type of assay used, where performed, turnaround time, and efficiency of use. Reviews of the types of parathyroid surgery and preoperative localization were included for educational purposes.Conclusions.-The intraoperative parathyroid hormone assay is a useful adjunct to preoperative imaging and parathyroid surgery because of its unique ability to detect an occult residuum of hyperfunctioning parathyroid tissue. Use of this assay will obviate the need for frozen section in most routine cases. The test facilitates minimally invasive parathyroidectomy for single parathyroid adenomas, which, in turn, improves cost-effectiveness and cosmetic outcome. Its use in patients with known preoperative multiglandular disease is promising but requires further study.

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.

Intraoperative quick parathyroid hormone assay in the surgical management of hyperparathyroidism

Intraoperative quick parathyroid hormone (QPTH) assay is claimed to prevent failure during parathyroidectomy for hyperparathyroidism. The causes of operative failure have included multiglandular disease, ectopic parathyroid glands, supernumerary parathyroid glands, errors in frozen section evaluations, and missed diagnosis. A QPTH assay has been recognized as a useful method of determining whether hyperfunctioning tissues have been completely excised. However, an intraoperative QPTH assay may fail to detect the presence of double parathyroid adenomas. Use of this assay in conjunction with preoperative and intraoperative localization studies has led to the advocacy of more directed cervical procedures, such as limited, video-assisted, and endoscopic parathyroidectomy.

Minimally invasive parathyroidectomy: the Australian experience

Minimally invasive parathyroidectomy (MIP) was introduced into Australia after endocrine surgeons agreed that it should only be undertaken in the context of a feasibility study or controlled trial, and under the auspices of the Australian Safety and Efficacy Register of New Interventional Procedures - Surgical (ASERNIP-S). Feasibility of endoscopic-assisted parathyroidectomy was studied at Royal North Shore Hospital (RNS) and 49 cases were completed. Subsequently, the technique of a focused lateral approach using a 2-cm incision placed directly over the site of the localized adenoma was developed and has now become the standard technique for the unit. To date, 357 MIPs using the focused lateral approach have been performed with a 1.5% rate of negative neck exploration and a permanent recurrent laryngeal nerve palsy rate of 0.8%. The use of intraoperative rapid measurement of parathyroid hormone (PTH, IO-QPTH) as an assessment of completeness of resection of abnormal parathyroid tissue has been replaced by simply measuring PTH levels 30 minutes postoperatively, a technique that is more cost-effective, and which still allows same-day discharge whilst avoiding false-positive results with IO-QPTH. The introduction of MIP appears to be a factor in the increasing number of referrals for parathyroid surgery.

Intraoperative parathyroid hormone testing: survey of testing program characteristics

OBJECTIVE

To examine the number and testing characteristics of laboratories that offer intraoperative testing of intact parathyroid hormone (PTH).

DESIGN

Laboratories (n = 355) that participated in 2001 in PTH proficiency testing with the College of American Pathologists Special Ligand Survey were surveyed about intraoperative PTH testing.

RESULTS

Of the 320 laboratories that responded to the survey, 92 performed intraoperative PTH testing. Testing practices were divided nearly equally among laboratories that performed intraoperative PTH testing for all parathyroidectomies (40%), most but not all cases (31%), and less than half of cases (30%). Testing frequency usually was low, with about two thirds of laboratories reporting 5 or fewer cases per month. A surprising finding was that, although intraoperative PTH testing originally became widely practiced as a point-of-care test, 71% of laboratories performed testing in a central laboratory, 6% in satellite laboratories, and only 23% in operating suites. A survey of methods showed that 33% used the manual QuiCk-Intraoperative test, 47% used the automated Immulite Turbo intact PTH assay, and 20% used other methods.

CONCLUSIONS

Intraoperative testing of intact PTH, although relatively new, has come into widespread practice during parathyroid surgery. Service delivery has evolved from a point-of-care model toward a central laboratory model, with this test serving as an illustrative example of factors that affect the balance between point-of-care and laboratory testing.

Minimally invasive parathyroidectomy using the 'focused' lateral approach. II. Surgical technique

BACKGROUND

This paper describes the technique of minimally invasive parathyroidectomy. The technique is based on a thorough understanding of the anatomy of the fascial planes in neck, the surgical pathology and embryology of parathyroid glands and precise anatomical interpretation of preoperative localization studies.

METHODS

Tissue trauma is minimized by using a 2.0 cm incision placed directly over the abnormal parathyroid gland and by removing the adenoma, without compromising the basic endocrine surgical principles of identification and preservation of recurrent laryngeal nerve, avoidance of any capsular breech, and ligation of the vascular pedicle.

RESULTS/CONCLUSIONS

With proper patient selection, this technique results in a failure rate of less than 4% and ensures that the incidence of complications, such as recurrent laryngeal nerve injury, remains comparable with that of standard open parathyroidectomy.

Minimally invasive parathyroidectomy using the 'focused' lateral approach. I. Results of the first 100 consecutive cases

BACKGROUND

A feasibility study of 'focused' minimally invasive parathyroidectomy (MIP) using a lateral approach was commenced in 1999. The aim of the present paper was to evaluate the effectiveness and safety of this procedure in the first 100 consecutive patients.

METHODS

This was a prospective, non-randomized case-control study. One hundred consecutive patients with primary hyperparathyroidism (mean age 63.1 years; 74 females, 26 males) who fulfilled the inclusion criteria underwent focused MIP between May 1999 and December 2000. The results for the first and last 50 consecutive patients were compared to see whether they were reflective of a learning curve. The role of intraoperative quick parathyroid hormone (QPTH) estimation was also evaluated.

RESULTS

Focused MIP was successfully completed in 93 of 100 patients, with seven conversions. Three (3.2%) of the 93 patients had persistent hyperparathyroidism. Quick PTH was measured in 81 patients and the results were true positive (for cure) in 72 patients, false negative in six patients, true negative in two patients and false positive in one patient. Transient recurrent laryngeal nerve paresis occurred in one patient. During the same time period, open parathyroidectomy was performed in 242 patients. The results were not different between the first and later 50 patients undergoing MIP, nor were the outcomes significantly different from patients undergoing open parathyroidectomy.

CONCLUSIONS

Focused MIP is a safe and effective operative approach for appropriately selected patients. Failed procedures were invariably related to shortcomings of the localization studies. Measurement of QPTH, although accurate, is unreliable in the presence of multigland disease.