Parathyroid surgical failures with misleading falls of intraoperative parathyroid hormone levels

Single Center Experience in the Surgical Management of Primary Hyperparathyroidism

Objectives.

As calcium included as a part of routine laboratory screening early diagnosis of primary hyperparathyroidism (PHPT) has been increased. Surgical resection of parathyroid adenoma or hyperplasia still is the mainstay of the treatment for most PHPT patients. The aim of this study was to evaluate of the surgical outcomes of patients with PHPT that referred to our ENT department of our University Hospital for the last 6 years.

Methods.

One hundred thirty-seven patients with PHPT who underwent parathyroid surgery in our clinic between October 2011 and January 2018 included in this retrospective study. Data on demographics, clinical findings, past medical history, preoperative laboratory values in 3 months, preoperative localizing imaging studies including ultrasonography (USG) and 99mTc-sestamibi (methoxyisobutyl isonitrile, [MIBI]) scan, operative findings, postoperative laboratory values, and pathology reports were recorded. MIBI scan and USG are used as the first-line modalities in our center. Single-photon emission computed tomography was used for challenging situations of re-exploration and ectopic parathyroid pathology. Four-dimensional computed tomography scanning is was preferred as the last imaging modality. Focused unilateral neck exploration (FUNE) was performed with intraoperative frozen section analysis as a routine procedure. Bilateral neck exploration (BNE) was used only in re-exploration, ectopic parathyroid, and with high suspicion of multigland disease.

Results.

Totally 137 patients (female:male, 3:3; mean age, 54.6±13.2 years) included in the study. Single parathyroid adenoma was found in 108 patients (78.8%). Most common adenoma localization was left inferior parathyroid gland (46.7%). FUNE was performed in 89.8% of the patients and BNE for 10.2% of the patients. Postoperative normocalcemia was reached in 132 patients and permanent hypocalcemia was observed in two patients. Persistence hypercalcemia observed in three patients. Postoperative pathology reports revealed three patients have parathyroid carcinoma.

Conclusion.

Preoperative imaging modalities is very important in parathyroidectomy surgery. Routine use of preoperative imaging modalities reduced the risk of complications in our clinic.

Challenges in the Management of Ectopic Parathyroid Pathologies: A Case Series of Five Patients

In primary hyperparathyroidism (PHPT) the diagnosis and treatment of ectopic parathyroid adenomas (EPTA) is a challenging process for head and neck surgeons. We present five patients with EPTA in different locations, along with an in-depth discussion of imaging modalities. We used sestamibi scintigraphy (MIBI) and ultrasound as first line imaging tools in asymptomatic hypercalcemia and PHPT. Single photon emission computed tomography (SPECT) was combined with MIBI or computed tomography (CT) if a parathyroid pathology was not localized initially. Four-dimensional parathyroid CT (4D-CT) was the last imaging modality preferred to localize the ectopic parathyroid gland. We performed focused unilateral neck exploration (FUNE) with intraoperative frozen section analysis as a routine procedure for imaging-detected lesions. Bilateral neck exploration was performed for re-exploration cases and imaging-negative cases. Histopathology confirmed EPTA and postoperative serum calcium normalized in all cases. 4D-CT is promising for ectopic parathyroid gland localization if all other imaging modalities fail. Despite the advancements in imaging, surgical experience continues to play the central role in the management of ectopic parathyroid pathologies.

Intraoperative determination of PTH concentrations in fine needle tissue aspirates to identify parathyroid tissue during parathyroidectomy

BACKGROUND

Exact tissue identification during parathyroidectomy is essential to successfully cure hyperparathyroidism. PTH level determination from tissue aspirates has been advocated as a "biochemical frozen section" for parathyroid tissue identification. We investigated the sensitivity and specificity of this method in a large cohort of consecutive patients who underwent parathyroidectomy in a tertiary referral center.

METHODS

PTH levels of 359 tissue aspirates were measured intraoperatively in 223 consecutive patients from March 2006 to December 2008. Suspected parathyroid and control tissues were aspirated with a standardized technique immediately after their excision. Samples were processed for quick-PTH assay with peripheral blood samples before and after excision. PTH levels from tissue aspirates were correlated with pathological diagnosis. The Mann-Whitney test was used to determine statistical significance (P < 0.05).

RESULTS

A total of 255 parathyroid (196 adenoma, 30 hyperplasia, 4 carcinoma, 25 normal parathyroid) and 104 nonparathyroid tissue (88 thyroid, 16 lymph node, thymus, or fat) aspirates were compared. A highly significant difference was found between PTH levels of parathyroid (8,120 +/- 2,711 pg/ml; interquartile range (IQR): 4,949-9,075) and nonparathyroid (0.8 +/- 9.29 pg/ml; IQR: 0.4-1.4) tissue aspirates (P < 0.005). This test is 100% sensitive and 100% specific to identify parathyroid tissue for values >84 pg/ml. Furthermore, PTH levels of pathological parathyroid aspirates (8,169 +/- 2,597; IQR: 5,634-9,109) were higher than that of normal parathyroid aspirates (4,130 +/- 2,952; IQR: 2,569-8,284; P = 0.0011).

CONCLUSIONS

PTH level determination from tissue aspirates is a highly reliable, quick, and simple method to differentiate parathyroid and nonparathyroid tissues during parathyroidectomy. This method can obviate frozen sections in patients undergoing surgery for hyperparathyroidism.

Spurious decline in intraoperative parathyroid hormone: false positives in parathyroid surgery

OBJECTIVES

The aims of this study were to (1) describe a false-positive result using a highly sensitive intraoperative parathyroid hormone (PTH) assay in an adult patient with primary hyperparathyroidism and (2) discuss the potential pitfalls of revision parathyroid surgery and the implication of various localization techniques described in the literature.

METHODS

A case report is described from a tertiary care university hospital. A literature review detailing diagnostic tools used to improve outcomes in parathyroid surgery is presented. The potential inaccuracies of intraoperative PTH assays are discussed.

RESULTS

We present a 71-year-old woman with primary hyperparathyroidism who was referred to our institution for revision surgery. The patient had preoperative sestamibi imaging that localized a right inferior parathyroid lesion. Intraoperatively, a specimen consistent with parathyroid tissue was removed and sent for frozen section. The intraoperative PTH levels were noted to decrease from 154 pg/mL (preincision) to 28 pg/mL (20 minutes postexcision). The frozen section results were consistent with a lymph node. This stimulated a 4-gland exploration, which confirmed normal left superior and inferior parathyroid glands. A 1.5-cm right retroesophageal parathyroid was subsequently discovered and excised. Final intraoperative PTH levels were 20 pg/mL.

CONCLUSION

Rapid PTH assays have become the mainstay of parathyroid surgery at many institutions; however, despite their accuracy, false-positive results are known to occur. We present a case of an inaccurate decline in intraoperative PTH and use this case report as a means to highlight some potential pitfalls of the test.

Intra-operative parathyroid hormone monitoring in patients with parathyroid cancer

BACKGROUND

Intra-operative parathyroid hormone (PTH) monitoring (IPM) is 97% accurate in predicting postoperative eucalcemia in sporadic primary hyperparathyroidism (SPHPT). However, its usefulness in parathyroid cancer has not been demonstrated. This study reports IPM accuracy during surgical resections for parathyroid cancer.

METHODS

Eight of 556 consecutive patients with SPHPT underwent parathyroidectomy using IPM and had parathyroid cancer. Operative success was defined as eucalcemia > six months and operative failure/persistent cancer as hypercalcemia within six months of parathyroidectomy. The IPM criterion for operative success was defined as a >50% decrease of peripheral PTH levels from the highest either pre-incision or pre-excision values, 10 minutes after resection.

RESULTS

In eight patients, 11 operations were performed. Ten operations (91%) resulted in >50% intra-operative PTH decrease. However, in only seven (70%) of these resections, eucalcemia was achieved for >6 months with five of these seven (71%) procedures being initial en bloc resections. The remaining 3/10 (30%) operations with >50% intra-operative PTH decrease resulted in operative failures. In the last operation, intraoperative parathormone monitoring (IPM) correctly predicted operative failure. IPM sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in predicting outcome were 100, 40, 70, 100, and 75%, respectively.

CONCLUSIONS

IPM with the criterion of >50% PTH drop from the highest level is less accurate in predicting operative success in parathyroid cancer when compared to SPHPT. A >50% intra-operative PTH level decrease in patients with parathyroid cancer, particularly in reoperative cases, is less predictive of complete resection. The initial recognition of this disease followed by proper resection remains essential in the treatment of parathyroid cancer.

Best practice no 183. Examination of parathyroid gland specimens

The pathological examination of parathyroid glands is an essential component of the evaluation of hyperparathyroidism. Traditionally, this has involved intraoperative frozen sections during bilateral surgical exploration of the neck, to confirm removal of parathyroid tissue. With recent developments in imaging, some diseased glands can be localised preoperatively, enabling removal by minimally invasive, targetted surgery, with or without additional non-histological intraoperative procedures to confirm the removal of all hyperfunctioning parathyroid tissue. This article reviews these developments and describes the ideal approach to reporting parathyroid specimens.